1572
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
1. Intr Introd oduc ucti tion on
Acet Acetic ic acid bact acteria eria (AAB) AB) are are stri stricct aerob erobes es tha that bel belong ong to have the abilit ability y to partia partially lly oxidiz oxidize e carbon carbon Alphaproteobacteria and have sources sources into a correspon correspondingorganic dingorganic compound compound,, such as ethanol ethanol to acetic acetic acid [1,2] [1,2].. This This featur feature e makes makes them them valua valuable ble bioca biocatal talyst ystss for a numb number er of usef useful ul appl applic icat atio ions ns,, but but at the the same same time time AAB AAB are are also also spoiling spoiling organism organismss in some fermentat fermentation ion processes processes [3] [3].. Acetic acid is the primary metabolite of AAB and is produce duced d from from the the bioc biocon onve vers rsio ion n of etha ethano noll thro throug ugh h two two reac reacti tion onss cata cataly lyze zed d by the the memb membra rane ne-b -bou ound nd pyrr pyrrol oloq oqui uino noli line ne quin quinon one e (PQQ (PQQ)– )–de depe pend nden entt alco alcoho holl dehy dehydr drog ogen enas ase e (ADH (ADH)) and and alde aldehy hyde de dehydrog dehydrogenase enase (ALDH). (ALDH). ADH oxidizes oxidizes the ethanol ethanol to acetaldeh acetaldehyde, yde, whichis whichis thenconv thenconvert ertedto edto aceti aceticc acid acid byALDHandreleasedintothe byALDHandreleasedintothe surrou surroundi nding ng enviro environm nment ent.. These These two two dehydr dehydroge ogenas nase e comple complexes xes are strictly strictly connecte connected d to the respirato respiratory ry chain, chain, which which transferselectransferselectron tronss thro throug ugh h ubiq ubiqui uino none ne (UQ) (UQ) to oxyg oxygen en,, whic which h acts acts as the the final final elec electr tron on acce accept ptor or.. The The acet acetic ic acid acid prod produc uced ed by the the part partia iall oxid oxidaation tion of etha ethano noll can can be furt furthe herr oxid oxidiz ized ed in the the cyto cytopl plas asm m by a set set of soluble soluble NaD(P) NaD(P)+ -depen -dependen dentt dehydr dehydrog ogena enases ses (ADH (ADH and ALDH) ALDH) via the tricarbo tricarboxylic xylic acid cycle, cycle, resulting resulting in so-called so-called acetate acetate oxidation oxidation (overoxidation) [4] [4].. Acet Acetic ic acid acid is the the main main comp compon onen entt in vine vinega garr and and is also also recrecogniz ognized ed as an effect effectiv ive e antim antimic icrob robial ial compou compound nd that that preven prevents ts the the growt growth h of patho pathogen genic ic and spoila spoilage ge organ organism ismss in fermen fermented ted foods; foods; it also also causes uses spoi spoilling ing in bever everag ages es suc such as wine, ine, in which it is detrim detriment ental al even even at concen concentra tratio tions ns as low as 1.2–1 1.2–1.4g/L .4g/L [5] [5].. Food-g Food-grad rade e vinega vinegar, r, which which is used used wor worldw ldwide ide as a preser preserva vativ tive e and and condi condimen mentt for food food [6] [6],, is a dilu dilute ted d solu soluti tion on of acet acetic ic acid acid and and is prod produc uced ed thro throug ugh h a micr microb obia iall oxid oxidat atio ion n carr carrie ied d out out by AAB AAB [7] [7].. In addi additi tion on,, vine vinega garr has has been been demo demons nstr trat ated ed to poss posses esss heal health thfu full properties [8] [8].. Vine Vinega garr brew brewin ing g can can be perf perfor orme med d by two two main main syst system ems. s. The The first first system system is solidsolid-sta state te fermen fermentat tation ion (SSF), (SSF), which which uses uses microo microorrganism isms grow grown n on subs substtrate ratess in the abse absen nce of free free water ater;; thi this syst system em is used used to prod produc uce e vine vinega garr from from grai grains ns in Asia Asian n coun countr trie ies. s. SSF SSF incl includ udes es thre three e main main biol biolog ogic ical al step steps: s: star starch ch liqu liquef efac acti tion on and and saccharifi saccharificati cation, on, alcohol alcohol fermentat fermentation ion and acetic acetic acid fermentat fermentation ion [9].. The [9] The seco second nd syst system em is liqu liquid id ferm fermen enta tati tion on,, whic which h comp compri rise sess a set set of tech techni niqu ques es deve develo lope ped d in West Wester ern n and and Euro Europe pean an coun countr trie ies. s. Amongthesetech Amongthesetechniq niques ues,, the the submer submergedsyste gedsystem m is used used to produc produce e vinega vinegarr at indust industria riall scale scale [10] (Fi Fig. g. 1). A subm submer erge ged d syst system em has has sever several al adva advant ntag ages es over over othe otherr tech tech-niques niques (e.g. (e.g. SSF and surface surface fermentat fermentation) ion),, includin including g highyield and proces processs speed.Over speed.Over thelast fewdecades, fewdecades, many many studie studiess have have examexaminedprocessvariables inedprocessvariables (oxygenavailabi (oxygenavailability,tempera lity,temperature,aceticacid ture,aceticacid andethanolcontent), andethanolcontent), and a number number of strategiesfor strategiesfor process process control control have have been been develo developed ped.. As a result result,, aceti aceticc acid acid fermen fermentat tation ion system systemss and the modern modern vinegar vinegar industrybenefit industrybenefit from robust robust processes processes and optimiza optimization tion tools tools [11–15] [11–15].. Majo Majorr stud studie iess have have also also been been cond conduc ucte ted d to exam examin ine e the the prev prevaalent lent micr microfl oflor ora, a, in orde orderr to dete determ rmin ine e the the role role of AAB AAB in vine vinega garr [16–24].. Differenc Differences es in the species species detected detected correlate correlate fermentation [16–24] withthe selectivepressure selectivepressure exerted exerted by the acetic acetic acidconcentratio acidconcentration n of collectio collection n sites.In particula particular, r, highly highly acidic acidic vinegar vinegar environm environments ents (ace (aceti ticc acid acid >6% >6% (w/v (w/v)) )) favo favorr the the prev preval alen ence ce of Gluconacetobacter specie species, s, whoseADH whoseADH shows shows a highe higherr stabil stabilityin ityin high high aceticacidconaceticacidcontent; tent; in low acidit acidity y vinega vinegars rs (acet (acetic ic acid acid concen concentra tratio tion n ≤6% (w/v) (w/v))) species es are domina dominant, nt, althou although gh Gluconacetobacter has Acetobacter speci alsobeen found found [25–27] [25–27].. Althoughthe Althoughthe aforement aforementione ioned d studies studies provide vided d a good good unde unders rsta tand ndin ing g of the the ecop ecophy hysi siol olog ogy y of AAB AAB in acid acidic ic niches niches,, very very little little litera literatur ture e is availa available ble on the functi function onali ality ty of AAB in submergedproces submergedprocesses ses relatingto relatingto process process parameter parameters. s. Thereasons for for this this lack lack of info inform rmat atio ion n can can be main mainly ly attr attrib ibut uted ed to the the diffi diffi-cult culty y of hand handli ling ng of AAB, AAB, resu result ltin ing g ofte often n in slow slow grow growin ing g cult cultur ures es,, especi especiall ally y those those derive derived d from from highl highly y acidic acidic vinega vinegars. rs.
Raw material a Addition
Upstream processing
of sulphur dioxide Centrifugation bBlending c
Addition of nutrients
alcoholic alco holic stock stocks s reuse of acetifying cultures for next cycle
Start-up
Acetification Fermentation
Downstream processing
Sedimentation Clarification Pasteurization Filtration a Addition
of sulphur dioxide
VINEGAR Fig. Fig. 1. Schematic Schematic represent representation ation of vinegar vinegar production production in submerged submerged system. system. a At concen concentra tratio tions ns specifi specified ed by legisl legislati ation on;; b blen blendi ding ng with with high high acid acidit ity y vine vinega gar, r, to block undesired undesired alcoholic alcoholic fermentat fermentation; ion; c nutrientscontainin nutrientscontaining g carbon carbon and nitrogen nitrogen source sources, s, vitami vitamins ns and minera minerals ls are supple supplemen mented ted especi especiall ally y to produc produce e high high acidacidity vinega vinegarr (>12% (>12% of acetic acetic acid) acid) from from alcoho alcoholic lic stocks stocks contai containin ning g no carbonsourc carbonsources es except except for ethanol ethanol [10] [10]..
In addit dditio ion n, it is well ell kno known that a larg large e frac fracttion ion of micr icroor oorgani ganism smss pres presen entt in both both natu natura rall and and indu indust stri rial al envi enviro ronm nmen ents ts are are uncultiv uncultivable able under standard standard laborato laboratory ry condition conditions. s. Environ Environment mentss in which ich viab iable but not cultiv ltiva able mic microo roorgan rganis ism ms have ave been een found found includ include e soil soil [28] [28],, activate activated-slu d-sludge dge process process for waste-wa waste-water ter treatment [29] [29],, clinic clinical al sample sampless exhibi exhibitin ting g mixed mixed commun communiti ities es of biofilm-forming biofilm-forming bacteria [30] [30],, vinegars [31] andpapermill[32] ndpapermill [32].. The uncult uncultiva ivabil bility ity phenom phenomeno enon n limits limits the the under understa standi nding ng of specie speciess rich richne ness ss and and dive divers rsit ity y of thes these e envi enviro ronm nmen ents ts and and cons conseq eque uent ntly ly a broad-spec broad-spectrum trum strategyto strategyto select select efficientstrains efficientstrains as starter starter culture culture is affected. affected. The The diffi difficu cult lty y of cult cultiv ivat atin ing g AAB AAB is one one of the the reas reason onss why why vinegar fermen fermentat tation ion is still still perfor performed med using using unsele unselect cted ed cultur cultures. es. Vine Vinega garr cons consum umpt ptio ion n has has been been incr increa easi sing ng year yearly ly worl worldw dwid ide e [33],, and [33] and unde unders rsta tand ndin ing g the the micr microb obia iall comp compos osit itio ion n and and acti activi vity ty of AAB AAB in subm submer erge ged d cond condit itio ions ns can can resu result lt in furt furthe herr proc proces esse sess opti optimi miza zati tion on,, posi positi tive vely ly impa impact ctin ing g prod produc ucti tion on yiel yield. d. More Moreov over er,, cons consum umer er dema demand nd for for high high adde addedd-va valu lue e prod produc ucts ts,, incl includ udin ing g ferferment mented ed and and low low sour sour beve bevera rage gess indi indica cate tess pote potent ntia iall appl applic icat atio ions ns for novel novel and and funct function ional al starte starterr cultur cultures. es. The presen presentt review review aims aims to outlin outline e the the main main featur features es of the aeraerobic obic subm submer erge ged d proc proces esss for for vine vinega garr prod produc ucti tion on at the the indu indust stri rial al scale scale and to overc overcome ome acetifi acetificat cation ion constr constrain aints ts in order order to furth further er enhance enhance processes processes optimiza optimization tion.. 2. Aerobi Aerobic c submer submerged ged fermen fermentat tation ion
AAB AAB are are expl exploi oite ted d for for the the comm commer erci cial al prod produc ucti tion on of a vari variet ety y of biomolecules including dihydroxyacetone dihydroxyacetone [34] [34],, 2-keto-l-gulonic acid, d-sorbitol [35] [35],, gluconic gluconic acid [36] [36],, using submerged submerged fermenfermentation tation (SF) processes. processes. SF for for vine vinega garr prod produc ucti tion on is an aero aerobi bicc proc proces esss by whic which h the the etha ethano noll in liqu liquid idss such such as spir spirit its, s, wine wine or cide ciderr is oxid oxidiz ized ed to acet acetic ic acid acid by AAB, AAB, in contro controlle lled d stirri stirring ng condi conditio tions ns [37] [37]..
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
The acetic acid fermentation proceeds according to the basi asic sto stoich ichiom iometri etricc equ equatio ation n C2 H5 OH+O2 → CH3 COOH+H2 O; (G◦ = −455kJ/mol). The sum of ethanol (mL per per 100 100 mL) mL) and acetic acid (g per 100mL) is call called ed ‘tot ‘total al conc concen entr trat atio ion’ n’ beca becaus use e it expr expres esse sess the the maxim maximal al concen concentra tratio tion n of acetic acetic acid acid that that can can be obtain obtained ed by comcomplete plete fermentat fermentation. ion. This calculati calculation, on, commonly commonly used in the vinegar vinegar industry [10] [10],, is based based on the the fact fact that,acco that,accordi rding ng to the the above above equaequation tion,, a 1M etha ethano noll solu soluti tion on (4.6g/ (4.6g/10 100mL) 0mL) prod produc uces es 6 g of acet acetic ic acid acid in 102 102 mL. mL. A solu soluti tion on of 4.6 4.6 g/10 g/100 0 mL etha mL ethanol nol correspon corresponds ds (in volu volume me)) to 5.8mL 5.8mL ethanol/100mL; 6g/102mL of acet cetic acid acid are are equi equiva vale lent nt to 5.9 5.9 g of acet acetic ic acid acid per per 100 100 mL. mL. The The quot quotie ient nt of the the tota totall vine vinega garr conc concen entr trat atio ion n prod produc uced ed over over the the total total mash mash concen concentra tratio tion n indica indicates tes the the yield yield (%) (%) and and expres expresses ses the the relati relation on betwee between n the the input input total total concen concentra tratio tion n and the the output output tota totall conc concen entr trat atio ion n of the the mash mash [10] [10].. Theore Theoretic ticall ally, y, the the total total conconcentratio centration n should should remain remain constantthroug constantthroughoutthe houtthe process.Because process.Because etha ethano noll is also also a carb carbon on sour source ce for for the the synt synthe hesi siss of cell cellul ular ar conconstit stitue uent nts, s, it can can be depl deplet eted ed at the the cyto cytopl plas asmi micc leve levell and and it can can be part partia iall lly y lost lost by evap evapor orat atio ion, n, so the the actu actual al yiel yield d is lowe lowerr than than the the theoretic theoretical al one [38] [38].. The basic basic requir requireme ement ntss for submer submerged ged proces processes ses are the the avail avail-ability ability of suitable suitable alcoholi alcoholicc stocks, stocks, uninterru uninterrupted pted aeration aeration and AAB strain strainss that that tolera tolerate te high high concen concentra tratio tions ns of acetic acetic acid acid and and ethan ethanol, ol, whic which h are are not not sens sensit itiv ive e to phag phage e infe infect ctio ions ns and and that that requ requir ire e smal smalll quant quantiti ities es of nutrie nutrients nts,, to produc produce e high high amoun amounts ts of aceticacid aceticacid [10] [10].. One One of the the most most impo import rtan antt feat featur ures es of the the bior biorea eact ctor orss used used in thes these e proc proces esse sess is the the aera aerati tion on syst system em.. This This syst system em cons consis ists ts of a holl hollow ow body body turb turbin ine e supp suppor orte ted d by a nonnon-ro rota tati ting ng stat stator or.. The The turturbine bine sucks sucks air from from the outsid outside e and and releas releases es it into into radial radial holes holes that that open open in the the oppo opposi site te dire direct ctio ion n of rota rotati tion on;; the the acti action on of turb turbin ines es result resultss in very very fine fine air bubble bubbless and and homoge homogenou nouss air–li air–liqui quid d disper disper-sion sion.. The The air– air–li liqu quid id emul emulsi sion on is push pushed ed upwa upward rdss and and dive divert rted ed by defle deflect ctor ors. s. All All of the the mass mass is main mainta tain ined ed in a cons consta tant nt stat state e of agiagitation tation to preven preventt the the forma formatio tion n of low oxygen oxygen tensio tension n areas, areas, which which are unfav unfavora orable ble for the the metabo metabolic lic activi activity ty of AAB [39,40] [39,40].. The The oxyg oxygen en tran transf sfer er is influ influen ence ced d by a high high numb number er of para parammeter eterss incl includ udin ing g phys physic ical al prop proper erti ties es of gas gas and and liqu liquid id,, oper operat atio iona nall cond condit itio ions ns and and geom geomet etri rica call para parame mete ters rs of the the bior biorea eact ctor or.. Ther Thereefore, fore, the oxygentrans oxygentransfer fer rate rate depend dependss on stirri stirring ng since since it facili facilitat tates es the the disr disrup upti tion on of larg large e bubb bubble less into into smal smalle lerr ones ones,, on the the surf surfac ace e tens tensio ion n of the the solu soluti tion on,, on the the visc viscos osit ity y and and on the the frac fracti tion on of gas gas reta retain ined ed in the the bior biorea eact ctor or.. A deta detail iled ed desc descri ript ptio ion n of the the oxyg oxygen en transf transfer er rate rate and and parame parameter terss that that affect affect its efficie efficienc ncy y in aerobi aerobicc SF can can be foun found d in [41,42] [41,42].. In stirre stirred d condit condition ions, s, the liquid liquid produc produces es foam, foam, which which can can lead lead to the the form format atio ion n of a redu reduci cing ng envi enviro ronm nmen entt and and comp compro romi mise se the the acet acetifi ifica cati tion on proc proces ess. s. Gene Genera rall lly, y, bior biorea eact ctor orss are are equi equipp pped ed with with a mechan mechanic ical al skimm skimmer, er, consis consistin ting g of a rotati rotating ng chamb chamber er with with radial radial wing wingss that that turn turn very very quic quickl kly; y; the the foam foam ente enteri ring ng into into the the cham chambe berr is cent centri rifu fuge ged. d. The The exha exhaus uste ted d gase gasess are are elim elimin inat ated ed from from an uppe upperr open openin ing, g, whil while e the the foam foam is conn connec ecte ted d to the the exha exhaus ustt duct duct [39] [39].. heat gene genera rati tion on duri during ng SF is unav unavoi oida dabl ble e beca becaus use e acet acetic ic The heat acid acid ferm fermen enta tati tion on is an exot exothe herm rmic ic reac reacti tion on,, prod produc ucin ing g appr approx oxiimate mately ly 8.4 8.4 MJ for for ever every y lite literr of oxid oxidiz ized ed etha ethano noll [39] [39].. Moreover, during during charg charge e of substr substrate ate and disch discharg arge e of produc product, t, the temper temperaature can varygreatly. Fermenta Fermentation tion breakdow breakdown n due to temperatu temperature re varia variatio tion n is genera generally lly avoid avoided ed by heatin heating g and coolin cooling g system systems. s.
1573
Submerged fermentat fermentation ion in semi-conti semi-continuous nuous mode for vinegar vinegar production production.. Fig. Fig. 2. Submerged Desirable Desirable achievemen achievements ts as a basic platform platform for processes processes optimizatio optimization n and product product innovation. a TC:total concentra concentration(sumof tion(sumof ethanoland ethanoland acetic acetic acidconcentratio acidconcentrations); ns); b slow slow load load of raw materi material/ al/qui quick ck unload unload of final final produc product. t.
Semi-c Semi-con ontin tinuou uouss operat operation ion is report reported ed to be the the most most advan advantatageou geouss for for vine vinega garr prod produc ucti tion on,, part partly ly beca becaus use e it redu reduce cess the the risk risk of substr substrate ate inhibi inhibitio tion n and catabo catabolit lite e repres repressio sion. n. Moreov Moreover, er, it allows allows forthe reuse reuse of theacetify theacetifyingcult ingculturein urein the the subseq subsequen uentt cycle cycle and and to obta obtain in prod produc ucts ts with with a wide wide rang range e of both both acet acetic ic acid acid and and etha ethano noll concentrations [10,11] (Fig. 2). Othe Otherr ferm fermen enta tati tion on mode modess have have been been eval evalua uate ted, d, espe especi cial ally ly for for the the prod produc ucti tion on of high high-t -tit iter er acet acetic ic acid acid,, whic which h is one one of the the main main dema demand ndss of vine vinega garr indu indust stry ry;; so far, far, the highest highest yields yields are obtainedby obtainedby usingthe semi-con semi-continu tinuous ous mode. mode. For For exam exampl ple, e, in usin using g cont contin inuo uous us mode mode,, a maxi maximu mum m of 9–10 9–10% % (w/v (w/v)) of acet acetic ic acid acid conc concen entr trat atio ion n is reac reache hed d beca becaus use e the the spec specifi ificc grow growth th rate rate of AAB AAB decr decrea ease sess at low low etha ethano noll conc concen entr trat atio ion n and and a highacetic acidcontent. acidcontent. Previous Previous comparat comparative ive studies studies showed showed that in cont contin inuo uous us cult cultur ure e at a tota totall conc concen entr trat atio ion n of 12%, 12%, the the spec specifi ificc growt growth h decrea decreased sed from from 0.027h 0.027h −1 at 4.5% 4.5% (v/v) (v/v) ethan ethanol ol to 0.006h 0.006h −1 at 1% (v/v) (v/v) ethano ethanol. l. Howeve However, r, no decrea decrease se of the specifi specificc growth growth rate rate was was observ observed ed by increasin increasing g theacetic acidconcentrat acidconcentrationsin ionsin semi-cont semi-continuo inuous us fermentation [43] [43].. Further Further experimen experiments ts have have confirmed confirmed this behavior behavior in both continuo continuous us and semi-cont semi-continuo inuous us condition conditionss [11] [11].. The simple simplest st semi-c semi-cont ontinu inuous ous operat operation ion mode mode is perfor performed med by twobioreact twobioreactors ors arrang arranged ed in series series.. Thefirst biorea bioreacto ctorr contai contains ns the inoc inocul ulum um deri derive ved d from from a prev previo ious us cycl cycle, e, to whic which h wine wine or othe otherr alcoh alcoholi olicc liquid liquidss (12–15 (12–15% % (v/v) (v/v) ethano ethanol, l, 1–2% 1–2% (w/v) (w/v) aceti aceticc acid) acid) are adde added. d. When When the the acet acetif ifyi ying ng mass mass reac reache hess an etha ethano noll cont conten entt of approx approxima imatel tely y 2–3% 2–3% (v/v) (v/v),, it is pumped pumped into into the the second second biorea bioreacto ctorr wher where e it will will rema remain in unti untill the the etha ethano noll is depl deplet eted ed (0 (0.2 .2–0 –0.3 .3% % (v/v (v/v)) )) and the the requir required ed acetic acetic acid acid conten contentt is achiev achieved ed [10] [10].. Thedurationof Thedurationof a fermen fermentat tationcycl ioncycle e is betwee between n 18 and30 h. The length length mainly mainly depend dependss on the initia initiall concen concentra tratio tion n of ethano ethanol, l, the effic efficie ienc ncy y of the the aera aerati tion on syst system em and and the the dura durati tion on of the the bact bacter eria iall lag lag phas phase. e. For For wine wine,, inte interv rval alss of 24h for for eachcyc eachcycle le were were opti optima mall to obtain obtain high high acetic acetic acid acid conc concent entrat ration ions; s; shorte shorterr interv intervals als provid provided ed high higher er acet acetifi ifica cati tion on rate ratess but but sign signifi ifica cant ntly ly lowe lowerr acet acetic ic acid acid conconcentra centratio tions. ns. Inter Interva vals ls of more more than than 30h betwe between en each each loadin loading g step step correl correlate ate with with instab instabili ility ty of cycles cycles [44] [44].. 3. Aceti Acetic c acid acid bacte bacteria ria in submer submerged ged fermen fermentat tation ion
2.1. Fermentation mode
SF at the industrial scale is primarily performed in a semi emiconti continu nuous ous mode mode (a repeat repeated ed fed-ba fed-batch tch proces process). s). In this this operat operation ion mode, mode, alcoho alcoholicsubst licsubstrat rates es are added added after after the the start start of the the aceti acetific ficaationand thenare addedintermitten addedintermittently,dependi tly,depending ng on consumpt consumption. ion.
Accordin According g to previous previous studies, studies, the indigeno indigenous us bacteria bacteriall populapopulation tion durin during g SF for vinega vinegarr produc productio tion n appear appearss quite quite homoge homogeneo neous, us, as it is mostly composed of the genus Gluconacetobacter and, and, in some some cases, cases, Acetobacter . More Moreov over er,, the the majo majori rity ty of stud studie iess iden iden-tify tify the the esta establ blis ishm hmen entt of a sing single le stra strain in or only only a few few stra strain inss of the the
1574
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
Table 1 Main Main acetic acetic acid acid bacter bacteria ia specie speciess in vinega vinegars rs produce produced d by differ differentsyste entsystems ms and their their resist resistanc ance e to ethano ethanoll and acetic acetic acid acid (expre (expresse ssed d as total total concen concentra tratio tion). n).
Speciesa
Total c on onc en entrati on on (%)
Vinegar
Cider
Wine
b
b
References
Spirit
Other Surface fe fermentation fo for TB TBV C ; SSF SSFd f or or cereal cereal vinegar vinegar – Surface Surface fermentat fermentation ion for TBVc
[9,23,26,27]
– – Kombucha Kombucha teag – Surface fermentation for TBV C ; SSF SSFd f or or cereal cereal vinegar vinegar
[25] [20,23] [19] [74] [22,23,47]
A. pasteurianus
8
SF
SF
–
A. aceti e Ga. europaeus europaeus
7 8–15
– SFb
SFb , Surface fermentation SFb
Ga. entanii entanii e Ga. hansenii hansenii e Ga. intermediu intermediuss e Ga. oboediens oboediens e Ga. xylinus xylinus
7 and 11 – 6f f ≤11 8
– SFb SFb – SFb
– Surface fermentation – SFb –
– SFb SFb SFb – SFb – –
[20,49] [18,23,27]
(–) not detected. detected. a A: Acetobacter genus; Ga: Gluconacetobacter genus. b SF: submerged fermentation. c TBV: traditional traditional balsamic balsamic vinegar. vinegar. d SSF: solid state fermentati fermentation. on. e Komagataeibacter accord according ing to Yamada Yamada and cowork coworkers ers [45] [45].. f Value Value obtain obtained ed with with experi experimen ments ts in tube tube test. test. g Low acidit acidity y bevera beverage ge obtain obtained ed by alcohol alcoholic ic and acetic acetic fermen fermentat tation ion in static static condit condition ions. s.
same same spec specie ies, s, sugg sugges esti ting ng the the form format atio ion n of a stab stable le envi enviro ronm nmen entt that that exerts exerts a stron strong g select selective ive pressu pressure, re, due mainly mainly to the the presen presence ce of acetic acetic acid acid [16–18] [16–18].. Howeve However, r, a great greater er degree degree of hetero heterogen geneit eity y has been been observ observed ed in indi indige geno nous us stra strain inss of cide ciderr vine vinega garr prod produc uced ed by SF, SF, when when comcompared pared to strain strainss of wine wine or spirit spirit vinega vinegars rs (Tab Table le 1). Reason Reasonss for this this phenomen phenomenon on could include include differenc differences es in raw materials materials,, processes processes or technica technicall condition conditionss during during fermentat fermentation. ion. Cider Cider vinega vinegars rs displa display y a wide wide range range of acetic acetic acid acid conten contentt (from (from 3.9 to 9.0% 9.0% (w/v) (w/v)), ), where whereas as wine wine and and spirit spirit vinega vinegars rs genera generally lly have have high higher er and and rest restri rict cted ed acet acetic ic acid acid cont conten ent, t, rang rangin ing g from from 4.4 4.4 to 8.0% 8.0% (w/v) (w/v) and and 11.5 11.5 to 12.2% 12.2% (w/v) (w/v),, respec respectiv tively ely [39] [39].. The less less string stringent ent condi conditio tions ns of aceti aceticc acid acid concen concentra tratio tion n during during SF could could be respon respon-sible sible for the wider wider divers diversity ity of specie speciess detect detected ed in cider cider vinega vinegars. rs. The The rele relev vanc ance of the the Gluconacetobacter genus in SF was first observed observed by Sievers Sievers andco-workers andco-workers [18] [18],, who identified Gluconacetobacter tobacter europaeus europaeus (now Komagata Komagataeibac eibacter ter europaeus europaeus) [45] as the main main compon component ent of the microfl microflora ora in indust industria riall biorea bioreacto ctors. rs. Some Some unique unique growthcond growthconditi itions ons for this this specie speciess are: are: abilit ability y to grow grow at pH 2.5,an acetic acetic acidconcentrati acidconcentration on of 10–14% 10–14% (w/v), (w/v), a constantoxygen constantoxygen europaeus supply supply and the requir requireme ement nt of acetic acetic acid. acid. Howeve However, r, Ga. europaeus has has also also freque frequent ntly ly been been isolat isolated ed from from low acidit acidity y vineg vinegars ars,, durin during g proces processin sing g steps steps with with consta constant nt acetic acetic acid acid conten contentt [27,31] [27,31].. Acetobacter pasteurianus and Acetobacter aceti, whos whose e stra strain inss have have a strong strong oxidativeactivit oxidativeactivity y against against ethanol,are ethanol,are mostly mostly found found as indigeno indigenous us organisms organisms in low acidity acidity vinegars vinegars (∼6%) [9,22,31,46] . In contrast contrast,, strains strains of Gluconacetobacter species es that that areableto Gluconacetobacter xylinus speci produc produce e suitab suitable le amoun amounts ts of acetic acetic acid acid can can have have an opposi opposing ng role role in vine vinega garr prod produc ucti tion on due due to thei theirr abil abilit ity y to synt synthe hesi size ze cell cellul ulos ose, e, thus thus potent potential ially ly causin causing g drawba drawbacks cks.. Howeve However, r, in surfac surface e fermen fermen-tation Ga. xylinus reported ed to have have a high high aceti aceticc acid acid produc productiv tivity ity;; xylinus is report this this is most most likely likely becaus because e the the struct structure ure of the the cellul cellulose ose membra membrane ne netw networ ork k supp suppor orts ts cell cellss clos close e to the the air– air–li liqu quid id inte interf rfac ace, e, faci facili lita tatting oxygen oxygen uptake uptake.. Conver Conversel sely, y, in shake shake condit condition ions, s, they they exhibi exhibited ted slowed slowed growt growth h and and lower lower substr substrate ate consum consumpti ption on [47] [47].. 4. Oxygen Oxygen avail availab abili ility ty in submer submerged ged fermen fermentat tation ion
AAB are obliga obligate te aerobi aerobicc bacter bacteria, ia, and and oxygen oxygen depriv deprivati ation on durduring ing SF caus causes es a rapi rapid d loss loss of prod produc ucti tivi vity ty.. Duri During ng SF, SF, the the leve levell of oxyg oxygen en cons consum umpt ptio ion n is dire direct ctly ly rela relate ted d to the the subs substr trat atee-to to-p -pro rodu duct ct conv conver ersi sion on and and it is link linked ed to the the AAB AAB growt growth h phase. phase. Theref Therefore ore,, durin during g the the lag phase phase,, the quanti quantity ty of conconsume sumed d oxyg xygen and the the acet acetic ic acid prod roduced uced is low low; duri uring the
expo expone nent ntia iall grow growth th phas phase, e, the the oxyg oxygen en cons consum umpt ptio ion n is high high and and is prop propor orti tion onal al to a high high prod produc ucti tion on rate rate of acet acetic ic acid acid [48,49] [48,49].. It has has been been stat stated ed that that the the effe effect ct of oxyg oxygen en depr depriv ivat atio ion n is dire direct ctly ly propor proportio tional nal to the total total concen concentra tratio tion, n, the the acetic acetic acid acid conce concent ntraration tion,, the the rate rate of ferm fermen enta tati tion on and and the the leng length th of the the inte interr rrup upti tion on of aera aerati tion on.. Prev Previo ious us expe experi rime ment ntss cond conduc ucte ted d on A. aceti under oxygen oxygen-de -defic ficien ientt condi conditio tions, ns, showed showed a strict strict corre correlat lation ion betwee between n the total total concen concentra tratio tion n and and cell cell damag damage. e. In partic particula ular, r, decrea decreases ses in etha ethano noll oxid oxidat atio ion n as well ell as of ADH ADH and and ALDH ALDH acti activi viti ties es (20 (20 and and 50%, 50%, respec respectiv tively ely)) wer were e observ observed ed after after interr interrupt uption ion of the the oxygen oxygen supp supply ly.. More Moreov over er,, enzy enzyma mati ticc dama damage ge incr increa ease sed d with with incr increa easi sing ng acidity; at an acetic acid content of greater than 4% (w/v) and etha ethano noll lowe lowerr than than 4.9% 4.9% (v/v (v/v), ), ADH ADH and and ALDH ALDH lost lost 60% 60% and and more more than than 90% of their their enzyma enzymatic tic activi activity ty in crude crude prepar preparati ation on,, respec respec-tively [50,51] [50,51].. In subm submer erge ged d cond condit itio ions ns of mixe mixed d AAB AAB cult cultur ure, e, it was was note noted d that that at a tota totall conc concen entr trat atio ion n of 5%, 5%, an inte interr rrup upti tion on of aera aerati tion on for for 2–8min had had the the same same effe effect ct as an inte interr rrup upti tion on for for 15–6 15–60 0 s when when the total total concentr concentration ation was 10–12% [10] [10],, wher wherea eass in SF of a cult cultur ure e A. aceti, an interr of A. interrupt uptionof ionof aerati aeration on for10 s at 6% (w/v)aceti (w/v)aceticc acid acid caused caused a total total inhib inhibiti ition on of acetic acetic acid acid produc productio tion n [51] [51].. Oxyg Oxygen en depr depriv ivat atio ion n can can be harm harmfu full not not only only duri during ng SF but but also also during during the transf transfer er of cultu cultures res from from the the precul precultiv tivati ation on flasks flasks to the the acet acetat ator orss and and duri during ng any any tran transf sfer er from from one one acet acetat ator or to anot anothe her. r. To redu reduce ce bact bacter eria ia deat death h and and to main mainta tain in a high high resp respir irat atio ion n acti activvity througho throughout ut the whole whole fermentat fermentation ion process, process, a so-called so-called RAMOS RAMOS (respirati (respiration on activitymonitori activitymonitoring ng system) system) device, device, thatensures a conconstant stant oxygen oxygen supply, supply, wasrecentlyproposed wasrecentlyproposed[52] [52].. Withthis method, method, cult cultur ures es drai draine ned d off off from from bior biorea eact ctor orss can can be tran transf sfer erre red d into into an aera aerate ted d bubb bubble le colu column mn and and tran transp spor orte ted d with withou outt an inte interr rrup upti tion on of the the oxyg oxygen en supp supply ly.. When When comp compar arin ing g bact bacter eria ia deat death h and and resrespira pirati tion on acti activi vity ty,, a high higher er numb number er of livi living ng cell cellss were were pres presen entt in cultures cultures transferr transferred ed by theRAMOS device device thanthose managedwith managedwith traditional procedures. Several Several investig investigation ationss havebeen conductedto conductedto evaluate evaluate the abilability of AAB to grow grow with with limite limited d oxygen oxygen conc concent entrat ration ionss [53,54] [53,54].. The earl earlie iest st resea researc rch h was was perf perfor orme med d usin using g wine wine,, wher where e AAB AAB caus causes es spoi spoila lage ge with with very very low low conc concen entr trat atio ions ns of diss dissol olve ved d oxyg oxygen en.. AAB AAB were were foun found d in bott bottle led d wine winess wher where e oxyg oxygen en in the the head headsp spac ace e was was enou enough gh for for grow growth th as well well as in wine wine stor stored ed in barr barrel els, s, wher where e oxyoxygenpermeate genpermeatess throu through gh the the wood wood at rate rate of 30mg/L per year, year, which which is suffic sufficien ientt for AAB surviv survival al [55] [55].. Howe Howeve ver, r, rela relati tive vely ly litt little le info inform rmat atio ion n is avai availa labl ble e rega regard rdin ing g the the opti optima mall oxyg oxygen en lev levels els requi equirred by AAB when perf perfo ormin rming g
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
biop biopro roce cess sses es.. In SF, SF, it was was foun found d that that duri during ng cont contin inuo uous us cult cultur ur- A. aceti in the ing ing of A. the expo expone nent ntia iall phas phase, e, the the opti optima mall rate rate of oxyg oxygen en cons consum umpt ptio ion n is abou aboutt 1 mg/L mg/L,, whic which h corr corres espo pond ndss to an acet acetic ic acid acid produc productio tion n of 45g/L [56] 45g/L [56].. Simi Simila larr resu result ltss (2mg/L (2mg/L of diss dissol olve ved d oxyg oxygen en)) have have been been foun found d in semi-c semi-con ontin tinuou uouss mode mode using using A. aceti, wher wherea eass the the same same cult cultur ure e in batch batch mode mode requir required ed less less oxygen oxygen (0.7mg/L (0.7mg/L of dissol dissolved ved oxygen oxygen)) [49,57].. Recentstudi [49,57] Recentstudies es on a Ga. xylinus strainfrom rice rice vinega vinegarr conconxylinus strainfrom firmed firmed the samebehavior, samebehavior, witha greater greater concent concentrati ration on of dissolved dissolved oxyg oxygen en pres presen entt (5.7 (5.76 6 mg/L mg/L)) in shak shakin ing g flask flask ferm fermen enta tati tion on than than in surface surface fermentat fermentation ion (0.3mg/L) [47] [47].. Duri During ng SF, SF, oxyg oxygen en is gene genera rall lly y supp suppli lied ed as a mixt mixtur ure e of air air at a high high flow flow rate rate.. As an alte altern rnat ativ ive, e, the the inte interm rmit itte tent nt use use of oxyg oxygen en-rich air at a lower flow rate was suggested [58] [58].. Oxygen-rich air is not used at the industrial scale because of the high cost of the the equi equipm pmen entt and and safe safety ty issu issues es for for mana managi ging ng high high-p -pre ress ssur ure e oxyg xygen. en. How However ever,, it could uld resu result lt in inc increa reases ses in proc proces esss yiel yield, d, impr improv ove e the the sens sensor oria iall char charac acte teri rist stic icss of the the vine vinega gar, r, and and redu reduce ce the loss of volatile volatile componen components, ts, includin including g ethanol. ethanol. Trials Trials conduct conducted ed at the the pilo pilott scal scale e show showed ed impr improv oved ed acet acetic ic acid acid prod produc ucti tivi vity ty (fro (from m 0.72g/L 0.72g/L/h /h with with air air to 1.35g/L 1.35g/L/h /h with with oxyg oxygen en-r -ric ich h air) air) and and a redu reducction tion in the total total proces processs time time using using 36%oxygen-r 36%oxygen-richair. ichair. Both Both lower lower (26% (26%)) and and high higher er (ove (overr 40%) 40%) oxyg oxygen en cont conten ents ts caus caused ed a decr decrea ease se in acetic acetic acid producti productivity vity [58] [58].. The inhibiti inhibition on of acetic acetic acid fermentafermentationat highoxygen concentr concentrationmay ationmay seem contradic contradictory tory because because oxygenis oxygenis thesubstrat thesubstrate e of the the aceti acetific ficati ation on reacti reaction on and and an increa increase se in the the oxyg oxygen en part partia iall pres pressu sure re shou should ld impr improv ove e the the oxyg oxygen en tran transsfer rate rate and hence hence the produc productiv tivity ity [40] [40].. Howeve However, r, a high high dissol dissolved ved oxyg oxygen en cont conten entt can can inhi inhibi bitt AAB AAB grow growth th by cont contri ribu buti ting ng to oxid oxidaative tive stre stress ss and and prot protei ein n dama damage ge in cell cellss [59] [59].. Moreov Moreover, er, during during SF a correl correlati ation on has been been observ observed ed betwee between n expone exponent ntial ial increa increases ses in acetalde acetaldehydeconcen hydeconcentrat trationwith ionwith ALDHinhibitionwhen ALDHinhibitionwhen theoxygen conte content nt is highe higherr than than 40% 40% [58] [58]..
5. Grow Growth th on etha ethano noll as carb carbon on sour source ce and and acet acetic ic acid acid resistance
speciess exhibi exhibitt three three growt growth h Acetobacter and Gluconacetobacter specie phase phasess in ethano ethanoll media. media. Altho Although ugh the the diauxi diauxicc growt growth-p h-pha hase se patpattern shows some variations from species to species, it can be gene genera rall lly y desc descri ribe bed d as foll follow ows: s: first first,, they they perf perfor orm m a rapi rapid d oxid oxidaation tion of ethan ethanol ol to acetic acetic acid, acid, which which is releas released ed from from the the peripl periplasm asm into into the the surrou surroundi nding ng enviro environme nment nt (the (the ethano ethanoll oxidat oxidation ion phase) phase).. Then,a Then,a statio stationa nary ry phase phase occurs occurs,, result resultingin ingin a decrea decrease se in viablecell viablecell numb number erss or low low grow growth th yiel yields ds (sta (stati tion onar ary y phas phase) e).. Fina Finall lly, y, ther there e is a secon second d expone exponenti ntial al phase phase (the (the aceta acetate te oxidat oxidation ion phase phase)) in which which acetic etic acid cid is catab atabol oliized zed by solu solub ble ADH ADH and ALDH LDH in the the cytoytoplasm, plasm, for both both energy energy genera generatio tion n and carbo carbon n assimi assimilat lation ion [4] [4].. Duri During ng etha ethano noll oxid oxidat atio ion n and and stat statio iona nary ry phas phases es AAB AAB accu accumu mu-late lated d acet acetic ic acid acid in the the envi enviro ronm nmen entt with withou outt util utiliz izin ing g it, it, whil while e during during overo overoxid xidati ation on phase phase (ethan (ethanol ol deplet depleted) ed) they they oxidiz oxidize e acetic acetic and H2 O. acid toCO2 and The The swit switch ch from from acet acetat ate e accu accumu mula lati tion on to acet acetat ate e oxid oxidat atio ion n is control trolle led d by changes ges in the meta etaboli bolicc flow flow thro throug ugh h the triricarb carbox oxyl ylic ic acid acid cycl cycle e [60] [60].. In Acetobacter and Gluconacetobacter three ree genes enes in the aar gene gene clus cluste terr are are requ requir ired ed for for acet acetic ic acid acid resistance: aarA encode encodess a citrat citrate e syntha synthase, se, aarB enco encode dess a func func-tion tional ally ly unkn unknow own n prot protei ein, n, and and aarC enco encode dess a prot protei ein n invo involv lved ed in acet acetic ic acid acid assi assimi mila lati tion on [61,62] [61,62].. Addit Addition ionall ally, y, the pmt gene encoding phoshatidylethanolamine phoshatidylethanolamine N -metyltransferase -metyltransferase [63] and the aatA gene gene encodi encoding ng an ATP-bi ATP-bind nding ing casse cassette tte transp transport orter er [64] are are invo involv lved ed in the the mech mechan anis ism m of acet acetic ic acid acid resi resist stan ance ce.. An efflu efflux x pump pump in the the cyto cytopl plas asmi micc memb membra rane ne spec specifi ificc for for acet acetic ic acid acid has has also also been been repo report rted ed as an addi additi tion onal al mach machin iner ery y in the the mech mechan anis ism m of acet acetic ic acid acid resi resist stan ance ce in AAB. AAB. When When cell cellss are are in the the pres presen ence ce of
1575
high high conce concent ntrat ration ionss of aceti aceticc acid acid the efflux efflux pump, pump, which which is driven driven by a prot proton on moti motive ve forc force, e, pump pumpss acet acetic ic acid acid from from the the cyto cytopl plas asm m to outsid outside e the the cell cell [65] [65].. 5.1. 5.1. Acetic Acetic acid acid resist resistanc ancee under under differ different ent condit condition ionss
Under Under industria industriall condition conditions, s, acetic acetic acid concentr concentratio ation n is a major major physio physiolog logica icall stress stressor or of cells. cells. Undis Undissoc sociat iated ed acetic acetic acid acid can penepenetrate trate thecell membrane membrane,, disruptin disrupting g membranetransp membranetransportprocesses ortprocesses,, and and then then diss dissoc ocia iate te insi inside de the the cell cell,, resu result ltin ing g in toxi toxicc leve levels ls of the the anion anion and an associ associate ated d increa increase se in acidit acidity y [66] [66].. Althou Although gh AAB are tole tolera rant nt to acet acetic ic acid acid at conc concen entr trat atio ions ns that that are are detr detrim imen enta tall to the majori majority ty of microo microorga rganis nisms, ms, signifi significan cantt varia variatio tion n among among AAB species species exists. exists. Moreover, Moreover, during during the different different fermentat fermentation ion phases phases of SF, SF, stra strain inss exhi exhibi bitt diff differ eren entt degr degree eess of resi resist stan ance ce to acet acetic ic acid acid.. This This resist resistan ance ce is affect affected ed by thenumber thenumber and and themodalit themodality y of recurrecursive sive cultiv cultivati ations ons in aceti aceticc acid acid media, media, and the time time betwee between n strain strain isolat isolation ion and indust industria riall applic applicati ation on [67–70] [67–70].. Ther Theref efor ore e the the effe effect ct of acet acetic ic acid acid on AAB AAB grow growth th is a func functi tion on of the the conc concen entr trat atio ions ns of subs substr trat ate e (eth (ethan anol ol)) and and prod produc uctt (ace (aceti ticc acid acid)) and and of the the grow growth th cond condit itio ions ns.. For For inst instan ance ce in shak shakin ing g etha ethano noll cult cultur ures es of Acetobac Acetobacter strain strains, s, it was was foun found d that that 10g/L of acet acetic ic acid acid has has an acti activa vati ting ng effect effect on growth, growth, and lower lower concentr concentration ationss resulted resulted in a significa significant nt decrea decrease se in the logari logarithm thmic ic growt growth h phase phase [71] [71].. Activ tivation tion and inhi nhibit bition ion effe effeccts on AAB grow rowth as a fun functio tion of the total otal conc oncentr entrat atio ion n have ave been been obse observ rved ed duri durin ng the star startt-up up phas phase e in SF. SF. In thes these e cond condit itio ions ns a tota totall conc concen entr trat atio ion n of approx approxima imatel tely y 8% (etha (ethanol nol betwee between n 35.5 35.5 and47 g/Land aceticacid aceticacid betw betwee een n 30 and and 45g/L) 45g/L) was was dete determ rmin ined ed to be opti optima mall for for a wine wine vinega vinegarr startstart-up,usingan up,usingan AABculture AABculture of theprevaili theprevailing ng A. aceti cells [48].. [48] Conv Conver erse sely ly,, duri during ng the the ferm fermen enta tati tion on step step AAB AAB are are able able to grow grow at higher higher concen concentra tratio tions ns of acetat acetate. e. The level level of acetat acetate e resist resistanc ance e depend dependss on the the physio physiolog logica icall adapta adaptatio tion n under under select selective ive pressu pressure re due due to acet acetic ic acid acid cont conten ent, t, with with sign signifi ifica cant nt vari variat atio ion n acco accord rdin ing g to spec specie ies, s, evol evolve ved d or wild wild-t -typ ype e stra strain inss (Ta Tabl ble e 2). Stra Strain inss of Ga. isolat ated ed from from indu indust stri rial al vine vinega garr bior biorea eact ctor orss tole tolera rate te europaeus isol acet acetic ic acid acid conc concen entr trat atio ions ns up to 100 100 g/L g/L [72] [72].. A. aceti in contin continuuous cultiv cultivati ation on with with ethan ethanol ol as substr substrate ate grows grows at concen concentra tratio tions ns of acetat acetate e exceed exceedin ing g 70g/L [56] 70g/L [56].. Moreover, Moreover, cultivat cultivation ion of A. A. aceti at increa increasin sing g acetat acetate e conc concent entrat ration ionss for long long period periodss of time time (corr (correespondi sponding ng to 240 genera generatio tions) ns) produc produced ed aceta acetatete-res resist istan antt cultur cultures es that that had had acqu acquir ired ed the the abil abilit ity y to grow grow at more more than than 50g/L 50g/L of acet acetic ic acid [68] [68].. 5.2. 5.2. Acet Acetic ic acid acid resi resist stan ance ce and and spec species ies
Accord ording ing to the the lite literratur ature, e, the high ighest est resi resist stan ancce again ainst acet acetic ic acid acid that that has has been been obse observ rved ed is desc descri ribe bed d for for the the foll follow owin ing g europaeus, Gluconacetobacter Gluconacetobacter intermedius, Gluconacetospecies: Ga. europaeus and Gluconacetobacter [18,19,25,26,73,74].. bacter bacter oboediens oboediens, and Gluconacetobacter entanii [18,19,25,26,73,74] Trˇ Trcek ce ˇ k and and co-w co-wor orke kers rs [26] dete detect cted ed high higher er ADH ADH acti activi vity ty in Ga. than in A. pasteurianus, indica indicatin ting g europaeus and Ga. interm intermedi edius us than that that the the expr expres essi sion on leve levell of ADH ADH in thes these e spec specie iess diff differ ers. s. High Higher er ADH ADH activ tivity mig might resu result lt in a big bigger ener energ gy pool ool ava availab ilable le for for memb membra rane ne-a -ass ssoc ocia iate ted d proc proces esse ses, s, such such as the the acet acetat ate/a e/ace ceti ticc acid acid export export system, system, which which may be involvedin involvedin the resistanc resistance e mechanism mechanism europaeus to high of Ga. europaeus high aceti aceticc acid acid conce concent ntrat ration ions. s. exhibits ts a shorte shorterr lagphase lagphase than than Ga. europaeus in Ga. intermedius intermedius exhibi etha ethano noll medi media, a, but but its its maxi maxima mall acet acetic ic acid acid resi resist stan ance ce is 40% 40% lowe lowerr than than that that of Ga. europaeus [26] [26].. Thes These e resu result ltss sugg sugges estt a diff differ eren entt adaptatio adaptation n mechanis mechanism m against against acetic acetic acidbetweenthe two species. Theisolatio Theisolation n sourceof sourceof theAAB might might partia partiallyexpla llyexplain in the the differ different ent beha behavi vior or towa toward rd high high conc concen entr trat atio ions ns of acet acetic ic acid acid.. For For inst instan ance ce,, the the test tested ed stra strain inss of Ga. intermedius report reported ed above above wer were e isolat isolated ed from from cide ciderr vine vinega gar, r, wher where e the the suga sugarr cont conten entt of the the appl apples es usua usuall lly y
1576
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
Table 2 Charac Character terist istics ics and/orgrowt and/orgrowth h condit conditionfor ionfor wild wild and engine engineere ered d acetic acetic acid acid bacter bacteria ia used used forethanol forethanol oxidat oxidation ion..
Organisma b
Ga. europaeus europaeus (DES11-DSM (DES11-DSM 6160) b Ga. europaeus europaeus V3 and and JK2 b Ga. intermediu intermediuss JK3 (LTH 4560 4560T ) Ga. entanii entanii (LTH A. pasteurianus SKU1108 A. pasteurianus TI and and TH-3 (thermo-adapted strain strain SKU1108) SKU1108) A. pasteurianus CICIM B7003-2 A. pasteurianus CWBI-B419 Acetobacter species A. tropicalis CWBI-B418 A. aceti subs. xylinum NBI1002 A. aceti subs. aceti 1023 A. aceti No. 116 A. aceti subsp. xylinum NBI2099 NBI2099 (pMV24) (pMV24) A. aceti subsp. xylinum NBI2099 NBI2099 (pAL25) (pAL25) A. aceti M23 a b c d
Yield (g/L acetic acid)
Characteristic/condition
References
90–95
High High acetic acetic acid acid tolera tolerance nce;; absolu absolute te requir requireme ement nt of acetic acetic acid acid
[18]
90–95c
High High acetic acetic acid acid tolera tolerance nce (10–8% (10–8% wt/v)) wt/v)) in broth broth
[26]
90–95c 90–95c
[26] [25]
30
Acetic Acetic acidtoleranc acidtolerance: e: 6% (wt/v) (wt/v) Cultiva Cultivatio tion n in an atmosp atmosphe here re at relati relative ve humidi humidity ty >95% >95% at total total concen concentra tratio tion n >6%; >6%; does does not over-o over-oxid xidize ize acetic acetic acidin AE broth brothd Thermotolerant (37 ◦ C)
[85]
30
Thermotolerant (40 ◦ C)
[85]
90
Physical mu mutation un under ac acidic st stress (6 (60 g/L ac acetic ac acid)
20
Thermotolerant (38 ◦ C) coupled coupled to acidoresist acidoresistant ant character character
20–30 20 80
Thermotolerant (3 (38–40 ◦ C) (up (up to 4% (wt/ (wt/v) v) acet acetic ic acid acid and and 8% (v/v (v/v)) etha ethano nol) l) Thermotolerant (35 ◦ C) coupled coupled to acidoresist acidoresistant ant character character Spheroplast fu fusion ac acetic ac acid to tolerance (5 (50 g/L) at at 30 30 ◦ C
30 60 68.4
Spheroplast fusion thermotolerant (37 ◦ C) Spheroplast fusion thermotolerant (37 ◦ C) Plasmid vector developed for Acetobacter
96.6
Cloning of of th the 75 75 kDa su subunit of of th the AL ALDH co complex of of A. polyoxogenes into pMV24 Continuous culture with 45 g/L acetic acid
c
50
[80] [84]
[83] [84] [78] [78] [78] [79] [79] [56]
Ga: Gluconacetobacter genus; A.: Acetobacter genus Komagataeibacter accord according ing to Yamada Yamada and cowork coworkers ers [45] [45].. Data Data obtain obtained ed from from yield yield reache reached d in high high acidit acidity y submer submerged ged fermen fermentat tation ion.. AE broth broth contai containin ning g 4% acetic acetic acid, acid, 3% ethano ethanol, l, 2% glucos glucose. e.
limi limits ts the the final final acid acidit ity y of vine vinega garr to 6%. 6%. In cont contra rast st,, stra strain inss of Ga. originate ated d from from 10% wine wine vineg vinegar. ar. Althou Although gh the the A. paseuropaeus origin teurianus test tested ed in this this comp compar arat ativ ive e stud study y were were also also deri derive ved d from from indust industria riall vinega vinegarr react reactors ors,, (with (with acetic acetic acid acid concen concentra tratio tion n higher higher than than 6% (w/v) (w/v)), ), its tolera toleranc nce e to acetic acetic acid acid was was lower. lower. These These result resultss are suppor supported ted by the fact fact that that the the majori majority ty of studie studiess report report A. pasteurianus as a commonspeci commonspecies es in low-ac low-acidi idity ty vinega vinegars, rs, andthere is no evid eviden ence ce for for a role role as a stab stable le comp compon onen entt of high high-a -aci cidi dity ty vine vine-gar microflora microflora.. A. pasteurianus was was prev previo ious usly ly foun found d as the the main main microb microbial ial compon component ent in SSF for cereal cereal vinega vinegars rs (appro (approxim ximate ately ly 6% (w/v) (w/v) acetic acetic acid concent concentrati ration) on) [9,75] [9,75];; other other studie studiess report reported ed the the suit suitab abil ilit ity y of stra strain inss of A. starte terr cult cultur ures es duri during ng A. pasteurianus as star the the scalescale-up up of static static fermen fermentat tation ionss with with aceti aceticc acid acid concen concentra tratio tion n main mainta tain ined ed in a rang range e betw betwee een n 1.7 1.7 and and 5% [27] [27].. Over Over the the past past few years, years, there there have have been been many many studie studiess attemp attemptting ing to unde unders rsta tand nd the the mech mechan anis isms ms of acet acetic ic acid acid resi resist stan ance ce,, and and also also for for stra strain in deve develo lopm pmen entt for for high high acid acidit ity y vine vinega garr prod produc ucti tion on [76–78] (Tab Table le 2). Fukaya Fukaya and co-worker co-workerss [78] developed eveloped a spherospheroplastfusion between between A. aceti subsp. aceti and A. aceti subsp. xylinum, which which showed showed enhanc enhanced ed aceti aceticc acid acid produc productio tion n at higher higher temper temper-atures atures (37 ◦ C). Furth Further er improv improved ed produc productio tion n of acetic acetic acid acid (1.4-f (1.4-fold old incr increa ease se resp respec ectt to wild wild stra strain in)) was was late laterr achi achiev eved ed by clon clonin ing g the the A. polyoxogenes into A. aceti [79] (Ta ALDH ALDH gene gene of A. Tabl ble e 2). Recently,UV Recently,UV mutagenes mutagenesis is under under acidic acidic stress stress was used to screen screen for for a ther thermo mo-a -ada dapt pted ed A. pasteurianus mutan utantt with ith a high igher ferferment mentat atio ion n abil abilit ity y (103g/ (103g/L L with within in 160 160 h) than than the the wild wild type type.. The The muta mutant nt also also show showed ed phen phenot otyp ypic ic stab stabil ilit ity y over over repe repeat ated ed cycl cycles es of semi-continuous semi-continuous fermentation [80] [80].. From From an indu indust stri rial al poin pointt of view view,, etha ethano noll oxid oxidat atio ion n and and acet acetic ic acid acid resi resist stan ance ce are are nece necess ssar ary y phen phenot otyp ypic ic trai traits ts for for stra strain inss to be effe effect ctiv ive. e. Howe Howeve ver, r, one one of the the limi limita tati tion onss of usin using g sele select cted ed AAB AAB strains strains in vinegarproduct vinegarproductionis ionis thatstrainscan losethese importan importantt phenotyp phenotypic ic traits traits over multiple multiple cultivat cultivation ion cycles. cycles. Previous Previous works works havereported thatthe characte characteristi ristics cs of AAB are stro strong ngly ly affe affect cted ed by the the “his “histo tory ry”” of stra strain inss [67] [67].. For instan instance, ce, the the
tole tolera ranc nce e to etha ethano noll and and acet acetic ic acid acid decr decrea ease sess when when isol isolat ates es have have been been used used as inoc nocula ula and then have been een kep kept for for a lon long tim time in shortshort-ter term m preser preserva vatio tion; n; a high high tolera toleranc nce e was was observ observed ed for strain strainss used used imme immedi diat atel ely y afte afterr the the isol isolat atio ion. n. This This inco incons nsis iste tenc ncy y is like likely ly due to the the geneti geneticc instab instabili ility ty of strain strains. s. Recursive Recursive cultivat cultivation ion of A. (NBRC RC 3283) 3283) produc produced ed a A. pasteurianus (NB high high rate rate of ethan ethanol ol oxidat oxidation ion-de -defic ficien ientt mutant mutants. s. The format formation ion of a multip multiphen henoty otype pe cell cell comple complex x with with differ different ent textur textures es (roug (rough h and smooth smooth)) of colon colony y surfac surfaces,as es,as a resultof resultof high high numberof numberof cultiv cultivati ation on cycles cycles,, was also also observ observed. ed. Geno Genomi micc anal analys ysis is of this this stra strain in reve reveal aled ed more more than than 280 280 tran transsposo poson ns and five five genes enes with ith hyperper-mu muta tabl ble e tan tandem repe repea ats in the the geno genome me.. The The geno genome me cons consis ists ts of a 2.92.9-Mb Mb chro chromo moso some me and and six six plas plasmi mids ds,, whic which h are are reco recogn gniz ized ed as char charac acte teri rist stic icss cont contri ribu butting to the hyper hyper-mu -mutab tabili ility ty [81] [81].. In contr contrast ast,, other other studie studiess report report more more phen phenot otyp ypic ic stab stabil ilit ity y of A. pasteurianus in terms of acetic acid acid prod produc ucti tion on for for stra strain inss main mainta tain ined ed with with a suit suitab able le long long-t -ter erm m pres preser erva vati tion on meth method od.. Inst Instea ead, d, phen phenot otyp ypic ic chan change gess can can aris arise e due due to mutati mutation on in subcul subcultur tures es preser preserved ved by shortshort-ter term m preser preserva vatio tion n [70].. These are stillstandingissues for establish [70] establishing ing stable stable industria industriall strain strains, s, and especi especiall ally y those those used used in highhigh-aci acidit dity y vinega vinegarr produc produc-tion. 6. Grow Growth th temp temper erat atur ure e
For indus industri trial al submer submerged ged condit condition ionss the optima optimall wor workin king g temtem◦ perature perature is approxima approximately tely 30 C [66] [66].. Temperatur Temperatures es increase increase above above the optimalvalue optimalvalue occurs occurs during during SF because because acetic acetic acidfermentatio acidfermentation n is a thermo thermody dynam namica ically lly favora favorable ble aerobi aerobicc proces process. s. A temper temperatu ature re increase increase induces induces the denatura denaturation tion of nucleic nucleic acids acids and proteins proteins and causes causes cell cell damage damage.. These These reacti reaction ons, s, togeth together er with with the the disper dispersio sion n of cellul cellular ar compo compound undss due to membra membrane ne damage damage,, can can irreve irreversi rsibly bly redu reduce ce the the meta metabo boli licc func functi tion onss of the the cell cellss [57] [57].. Addition Additionally, ally, the toxi toxicc effe effect ctss of acet acetic ic acid acid conc concen entr trat atio ion n in the the medi medium um incr increa ease se the sensit sensitivi ivity ty of AAB to high high temper temperatu atures res..
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
De Ory Ory and co-wo co-worke rkers rs [57] f ound o und that that in wine wine vinega vinegarr produc produc-tion tion the optima optimall temper temperatu ature re to maximi maximize ze the the specifi specificc growth growth rate rate of A. 30.9 ◦ C. The maximum maximum temperatu temperature re beyond beyond which which bac A. aceti is 30.9 teri terial al grow growth th was was tota totall lly y inhi inhibi bite ted d was was 35 ◦ C, whil while e the the mini minimu mum m ◦ temper temperatu ature re was was 8 C (les (lesss than than 1% of the the spec specifi ificc grow growth th rate rate). ). The The effe effect ct of temp temper erat atur ure e on acet acetic ic acid acid ferm fermen enta tati tion on in the the semi semi-c -con onti tinu nuou ouss proc process ess for for wine wine vine vinega garr prod produc ucti tion on was was also stud studie ied, d, util utiliz izin ing g both both isot isothe herm rmal al and and a grad gradie ient nt-t -tem empe pera ratu ture re approach [82] [82].. The The resu result ltss show showed ed that that the the over overal alll prod produc ucti tivi vity ty ◦ improved improved (approxim (approximately15–20% ately15–20%)) whenusing a 32–30 32–30 C decreasdecreasing temperatu temperature-g re-gradie radient nt condition condition,, with a concomit concomitant ant reduction reduction in the process time from 29 to 24.5h, compared to isothermal cond condit itio ions ns at 30 ◦ C. In this this expe experi rime ment nt,, an init initia iall temp temper erat atur ure e of ◦ 32 C was was maint maintain ained ed until until an aceti aceticc conce concent ntrat ration ion of 95g/L (start (start-ing ing from from 70g/L) 70g/L) was was reac reache hed, d, at whic which h poin pointt the the temp temper erat atur ure e was was gradu graduall ally y reduce reduced d to 30 ◦ C and and main mainta tain ined ed unti untill the the end end of the the proprocess cess.. The The use use of a temp temper erat atur ure e grad gradie ient nt is an appe appeal alin ing g pros prospe pect ct for both both improv improving ing the the proces processs produc productiv tivity ity and reduci reducing ng coolin cooling g expenses. The The avai availa labi bili lity ty of stra strain inss that that are are able able to prod produc uce e acet acetic ic acid acid at temper temperatu atures res other other than than the optima optimall values values for mesoph mesophili ilicc AAB AAB have have been been consi consider dered ed by severa severall author authorss (Tab Table le 2). Thermotolerant strain inss thatare thatare able able to acet acetif ify y at 38to 40 ◦ C with with highe higherr Acetobacter stra fermentat fermentationrates ionrates at higher higher temperatu temperatures res wereisolatedfrom fruits fruits [83].. Strain [83] Strainss of the the specie speciess Acetobacter tropicalis and A. pasteurianus were were isol isolat ated ed from from diff differ eren entt prod produc ucts ts in subsub-Sa Saha hara ran n Afri Africa ca and and select selected ed for their their capac capacity ity to produc produce e high high aceticacid aceticacid conten contentt at 35 and and 38 ◦ C, respectiv respectively ely [84] [84].. Addi Additi tion onal ally ly,, a numb number er of atte attemp mpts ts to obta obtain in ther thermo moto tole lera rant nt mutant mutantss have have been been made. made. A geneti genetical cally ly modifie modified d A. aceti strain strain was isolat isolated ed that that produc produced ed suitab suitable le acetic acetic acid acid conc concent entrat ration ionss at 37 ◦ C in continuo continuous us acetic acetic acid fermenta fermentation tion with1–2% (v/v) (v/v) ethanol ethanol [78] (Ta Tabl ble e 2). Recently, Recently, thermo-a thermo-adapt dapted ed strains strains (wh (which ich stably stably perform perform acetic acetic acid acid fermen fermentat tation ion at 40 ◦ C) wer were e obtain obtained ed by recurs recursive ive cultiv cultivati ation on cycles cycles using using A. pasteurianus (SKU1108) [85] [85].. It is well well knownthattherm knownthatthermoto otoler lerantAAB antAAB canaccumu canaccumulat late e a large large numbe numberr of mutati mutations ons during during the adapta adaptatio tion n to high high temper temperatu atures res nich niches es and and evol evolve ve defe defens nse e mech mechan anis isms ms agai agains nstt ther therma mall stre stress ss.. Thes These e mech mechan anis isms ms cont contri ribu bute te to an incr increa ease se in gene geneti ticc dive divers rsit ity, y, and ind induce uce the exp express ressio ion n of a wide ide varie arietty of str stressess-re resp spo onse genes genes and and altern alternati ative ve metabo metabolic lic pathw pathways ays.. Recent Recently ly some some studie studiess have have elucid elucidate ated d therole of a numberof numberof genes genes involv involved ed in AAB AAB therthermotoleran motolerance.Three ce.Three genes genes playa crucialrole crucialrole in thermoto thermotoleran lerance ce and ferm fermen enta tati tion on at high high temp temper erat atur ure e by AAB: AAB: the the amin amino o acid acid tran transsporter porter (APT (APT 1698) 1698),, the the transc transcrip riptio tiona nall regula regulator tor MarR MarR (APT (APT 2081) 2081) and and the C4-dic C4-dicarb arboxy oxylat late e transp transport orter er (APT (APT 2237) 2237) [85] [85].. An analysis analysis of genes genes involvedin involvedin the thermoto thermotoleran lerance ce mechanismof mechanismof A. A. tropicalis SKU1 SKU110 100 0 reve reveal aled ed a comp comple lex x of 24 gene geness resp respon onsi sibl ble e for for ther thermo mo-toler oleran ancce. In addit dditio ion n to genes enes inv involv olved in heat eat sho shock or str stress ess respon response, se, other other genes genes wer were e identi identified fied,, includ includin ing g those those requir required ed for cell cell cycl cycle e and and cell cell divi divisi sion on,, whic which h may may be rela relatted to DNA repli epli-errorrs and dam damage age at high igh temp emperat eratur ure, e, and and also lso tho those cation erro invo involv lved ed in cell cell wall wall or cell cell memb membra rane ne bios biosyn ynth thes esis is whic which h play play impo import rtan antt role roless as the the first first line line of defe defens nse e agai agains nstt envi enviro ronm nmen enta tall stress [86] [86].. A deep deeper er unde unders rsta tand ndin ing g of the the mole molecu cula larr mech mechan anis isms ms regu regu-lati lating ng heat heat-s -str tres esss adap adapta tati tion on coul could d lead lead to impr improv ovem emen ents ts in SF, SF, includin including g an innovati innovative ve high-tem high-temperat perature ure fermentat fermentation ion system. system. 7. Conc Conclu lusi sion on
SF is the the main main meth method od used used to prod produc uce e vine vinega garr at the the indu indust stri rial al sca scale. le. Alt Althoug ough acet acetic ic acid acid in vineg inegar ar can be der derived ived fro from syn synthet thetic ic path pathwa ways ys,, the the bioc biocon onve vers rsio ion n of etha ethano noll into into acet acetic ic acid acid is used used wor worldw ldwide ide to produc produce e food-g food-grad rade e vinega vinegar. r.
1577
The The avai availa labi bili lity ty of oxyg oxygen en,, acet acetic ic acid acid,, etha ethano noll and and the the proc proces esss temperatu temperature re are key factors factors for successful successful fermentat fermentation ion processes. processes. Historica Historically, lly, the developm development ent of the vinegar vinegar producti production on techniqu techniques es has formed formed two two principa principall technolo technologica gicall fronts: fronts: optimizin optimizing g process process cont contro roll and and the the eval evalua uati tion on and and deve develo lopm pmen entt of opti optimi mize zed d AAB AAB strain strains. s. Howeve However, r, these these effort effortss have have notmet the industria industriall demand demand for stable stable and robust robust strain strains. s. Althou Although gh many many studie studiess report report the the succes successfu sfull geneti geneticc improv improveement ent of AAB AAB str strain ains, which ich are are mainly inly sele seleccted ted for for acet acetic ic acid acid resist resistanc ance e and therm thermoto otoler leranc ance, e, it must must be emphas emphasize ized d that that all of the the atte attemp mpts ts have have been been cond conduc ucte ted d on Acetobacter spec specie ies, s, and and no stud studie iess have have been been done done on Ga. europa otherr more more suit suitab able le europaeus eus or othe specie speciess for SF. Base Based d on curr curren entt know knowle ledg dge, e, it is clea clearr that that AAB AAB spec specie iess show show signifi significan cantt variab variabili ility ty in the the techn technolo ologi gical cal charac character terist istics ics that that are import importan antt for vinega vinegarr produc productio tion. n. Theref Therefore ore,, the the select selection ion of optioptimal AAB strains is a very important means of increasing the produc productiv tive e capac capacity ity of this this sector sector,, andso far hasnot been been explor explored. ed. In light light of this, this, the the fastes fastestt progre progress ss may come come from from theselectio theselection n andvalidat andvalidationof ionof AAB AAB forpure techn technolo ologic gical al featur features,such es,such as acetic acetic acid tolerance tolerance and thermotol thermotoleranc erance. e. This advancem advancement ent could could then serve serve as basic basic platfo platform rm for the the searchof searchof functi function onal al starte starters rs in order order to increa increase se nutrit nutrition ional al and and qualit quality y benefit benefits. s. Fina Finall lly, y, many many AAB AAB meta metabo boli lite tess are are able able to inhi inhibi bitt the the grow growth th of undesi undesirab rable le microo microorga rganis nisms, ms, displa display y nutrac nutraceut eutica icall proper propertie ties, s, and contri contribut bute e to flavour flavour and and textur texture e proper propertie ties. s. The study study of spespecific cific meta metabo boli lite tess prod produc uced ed by AAB AAB is a prom promis isin ing g field field for for futu future re resear research ch that that is of indust industria riall intere interest. st. Contributors
M.G.conceivedof M.G.conceivedof thestudy andits design, design, coordina coordinatedthe tedthe study and and help helped ed to draf draftt the the manu manusc scri ript pt.. E.V. E.V. draf drafte ted d and and revi review ewed ed the the manusc manuscrip ript. t. M.C. M.C. drafte drafted d the introd introduct uction ion and tables tables.. M.G. M.G. and E.V. E.V. drafted drafted figures figures in close close collabora collaboration tion.. Allauthorsread andapproved the final manuscrip manuscript. t. Acknowledgement
The The auth author orss are are than thankf kful ul to Prof Profes esso sorr P. Giud Giudic icii for for his his sugg sugges es-tions tions on prepar preparing ing the manusc manuscrip ript. t. References [1] Adach Adachii O, Mo Moon onma mang ngme mee e D, To Toya yama ma H, Ya Yama mada da M, Shina Shinagawa gawa E, Matsu Matsushita shita K. New dev develo elopme pments nts in oxi oxidat dative ive fer fermen mentat tation ion.. App Appll Mic Microb robiol iol Bio Biotec techn hnol ol 2003;60:643– 2003;60:643 –53. [2] De Depp ppen enme meie ierr U, Eh Ehre renr nrei eich ch A. Ph Phys ysio iolo logy gy of ac acet etic ic ac acid id ba bact cter eria ia in li ligh ghtt of Gluconobac nobacter ter oxyda oxydans ns. J Mol Micro the gen genome ome se seque quence nce of Gluco Microbiol biol Biote Biotechno chnoll 2009;16:69– 2009;16:69 –80. [3] Mam Mamlou louk k D, Gul Gullo lo M. Ace Acetic tic aci acid d bac bacter teria: ia: phy physio siolog logy y and car carbonsourc bonsources es oxi oxi-dation.. Indi dation Indian an J Micro Microbiol biol 2013;5 2013;53:377 3:377– –84. [4] Mat Matsus sushit hita a K, Toy Toyama ama H, Ada Adachi chi O. Res Respir pirato atory ry cha chains ins in ace acetic tic aci acid d bac bacter teria: ia: membra mem brane ne bou bound nd per peripl iplasm asmic ic sug sugar ar and alc alcoho oholl res respir pirati ations ons.. In: Zan Zannon nonii D, editor edi tor.. Res Respir pirati ation on in Archaea and Bacteria, ad adva vanc nces es in ph phot otos osyn ynth thes esis is an and d respiratio respi ration. n. Dordr Dordrecht: echt: Sprin Springer; ger; 2004. p. 81 81– –99. [5] Ribére Ribéreau-Ga au-Gayon yon J, Peyn Peynaud aud E, Ribér Ribéreau-G eau-GayonP, ayonP, Sudra Sudraud ud P. Traitéd’œnologi Traitéd’œnologie. e. Scienceset Scien ceset techn techniquesdu iquesdu vin.Caractère vin.Caractèress desvins, matura maturationdu tiondu raisi raisin, n, levur levures es et bac bactér téries ies.. Par Paris: is: Dun Dunod;1975. od;1975. Tom Tome e 2. [6] Gi Giud udic icii P, Gu Gull llo o M, So Soli lier erii L, Fa Falc lcon one e PM PM.. Techn Technologi ological cal and micro microbiolog biological ical aspect asp ectss of tra tradit dition ional al bal balsam samic ic vin vinega egarr and the their ir infl influen uence ce on qua qualit lity y and sen sen-sorial sor ial pro proper pertie ties. s. Adv Foo Food d Nut Nutrr Res2009;5 Res2009;58:1 8:137 37– –82. [7] RogersP,ChenJS,ZidwickMJ. Organi Organicc acidand solve solventproductio ntproduction n PartI: Aceti Acetic, c, lactic,, glucon lactic gluconic, ic, succin succinic ic and polyh polyhydro ydroxyalka xyalkanoicacids. noicacids. In:Dworkin M, edito editor. r. Prokar Pro karyot yotes.New es.New Yor York, k, NY: Spr Spring inger;2006. er;2006. p. 511 511– –755. [8] Ver Verzel zellon lonii E, Tagl Tagliaz iazucc ucchi hi D, Con Conte te A. Rel Relati ations onship hip bet betwee ween n the ant antiox ioxida idant nt propertiesand prope rtiesand thephenolicand flavon flavonoid oid conte content nt in tradit traditionalbalsamicvineionalbalsamicvinegar. Food Chem 2007;1 2007;105:564 05:564– –71. Acetobacter pasteurianus strains [9] Wu J, Gu Gull llo o M, Ch Chen en F, Gi Giud udic icii P. Di Dive vers rsit ity y of Acetobacter isol is olat ated ed fr from om so soli lidd-st stat ate e fe ferm rmen enta tati tion on of ce cere real al vi vine negar gars. s. Cur Currr Mi Micr crob obio ioll 2010;60:280– 2010;60:280 –6.
M. Gullo Gullo et al./ Proces Processs Bioche Biochemi mistr stry y 49 (2014) (2014) 1571–1 1571–1579 579
[72] Trˇ Trcek ˇ J, Jer Jernej nejcc K, Mat Matsus sushit hita a K. The hig highly hly tol tolera erant nt ace acetic tic acidbacter acidbacterium ium Gluconacetoba conac etobacter cter europa europaeus eus ad adap apts ts to th the e pr pres esen ence ce of ac acet etic ic ac acid id by ch chan ange gess in lipid compo compositio sition, n, morph morphologic ological al prope propertiesand rtiesand PQQ-d PQQ-depen ependent dent ADH expre expresssion.. Extr sion Extremoph emophiles iles 2007; 2007;11:627 11:627– –35. [73] Sieve Sievers rs M, Teu Teuber ber M. Acetobacter europaeus in vin vinega egarr pro produc ductio tion. n. J Appl Bac Bac-teriol 1995;79(Suppl):84 1995;79(Suppl):84– –95. Acetobacter oboediens sp. nov. [74] Soko SokollekSJ, llekSJ, Hert Hertel el C, Hamm Hammes es WP. Descr Descriptionof iptionof Acetobacter and Acetobacter pomorum sp. nov., tw two o ne new w sp spec ecie iess is isol olat ated ed fr from om in indu dust stri rial al vinegar vineg ar ferme fermentati ntations. ons. Int J Syst Bacte Bacteriol riol 1998;4 1998;48:935 8:935– –40. [75] Nan Nanda da K, Tan Taniguc iguchi hi M, Uji Ujike ke S, Is Ishi hiha hara ra N, Mo Mori ri H, On Ono o H, Mu Muro rook oka a Y. Ch Char arac ac-teriza ter izatio tion n of ace acetic tic aci acid d bac bacter teria ia in tra tradit dition ional al ace acetic tic aci acid d fer fermen mentat tation ion of ric rice e vinegar(Komesu)and vineg ar(Komesu)and unpol unpolishe ished d ricevinegar(Kuros ricevinegar(Kurosu)producedin u)producedin Japan Japan.. Appl Environ Envir on Micro Microbiol biol 2001;6 2001;67:986 7:986– –90. [76] Ohm OhmoriS, oriS, Uoz UozumiT, umiT, Bep Beppu pu T. Los Losss of ace aceticacid ticacid res resist istanc ance e andethan andethanol ol oxi oxidiz diz-ing in g ab abil ilit ity y in an Acetobacter str strain ain.. Agr Agric ic Bio Bioll Che Chem m 198 1982;4 2;46:3 6:381 81– –9. [77] [77] Mull Mullin inss E, Kapp Kappoc ock k TJ. TJ. Func Functi tion onal al anal analys ysis is of the the acet acetic ic acid acid resi resist stan ance ce (aar (aar)) gene cluster cluster in Acetob Acetobact acter er aceti aceti strain strain 1023. 1023. Acetic Acetic Acid Acid Bacter Bacteria ia 2013;2( 2013;2(1), 1), http://dx.doi.org/10.4081/aab.2013.s1.e3.. http://dx.doi.org/10.4081/aab.2013.s1.e3 [78] Fukay Fukaya a M, Taga TagamiH, miH, Tay TayamaK, amaK, Oku Okumur mura a H,Kawam H,KawamuraY, uraY, Bep BeppuT. puT. Sph Sphero eropla plast st fusi fu sion on of Acetobacter aceti an and d it itss ap appl plic icat atio ion n to th the e br bree eedi ding ng of st stra rain inss fo forr vinegar vineg ar produc production tion.. Agric Biol Chem 1989;5 1989;53:2435 3:2435– –40. [79] Fuk Fukaya aya M, Ta Taya yama ma K, Ta Tama maki ki T, Ta Taga gami mi H, Ok Okum umur ura a H, Ka Kawa wamu mura ra Y, Be Bepp ppu u T. Cloning Cloni ng of the memb membranerane-bound bound aldeh aldehyde yde dehyd dehydrogen rogenase ase gene of Acetobacter polyoxogenes and imp improv roveme ement nt of ace acetic tic acid pro produc ductio tion n by use of the clo clone ned d gene.. Appl Envir gene Environ on Micro Microbiol biol 1989;5 1989;55:171 5:171– –6.
1579
[80] QiZ, Wa WangW, ngW, Ya Yang ng H,Xia X,Yu X.Muta X.Mutati tionof onof Acetobacter Acetobacter pasteurianus byUV irradiationunder irradi ationunder acidicstress for highhigh-acidit acidity y vineg vinegar ar ferm fermentat entation. ion. Int J Food Sci Techn Technol ol 2013;4 2013;49:468 9:468– –76. [81] Az Azum uma a Y, Ho Hoso soya yam ma A, Ma Mats tsut utan anii M, Fu ru ruya N, Horikawa H, Harada T, Hiraka Hir akawa wa H, Kuh Kuhara ara S, Mat Matsus sushit hita a K, Fuj Fujita ita N, Shi Shirai rai M. Who Wholele-gen genome ome ana anallysess rev yse reveal eal gen geneti eticc ins instab tabili ility ty of Acetobacter pasteurianus. Nu Nucl clei eicc Ac Acid idss Re Ress 2009;37:5768– 2009;37:5768 –83. [82] Frega FregapaneG, paneG, RubioRubio-Fern FernándezH, ándezH, Salvad Salvador or MD. Influe Influence nce of ferm fermentat entation ion temperatu per ature re on sem semi-c i-cont ontinu inuous ous ace acetifi tificat cation ion for win wine e vie vienga ngarr pro product duction ion.. Eur Food Res Techn Technol ol 2001;2 2001;213:62 13:62– –6. [83] Sae Saeki ki A, The Theera eragoo gooll G, Mat Matsus sushit hita a K, Toy Toyama ama H, Lot Lotong ong N, Ada Adachi chi O. Dev Develo eloppmentt of the men thermo rmotol tolera erant nt ace acetic tic acidbacte acidbacteria ria use useful ful forvineg forvinegar ar fer fermen mentat tationat ionat higherr tempe highe temperature ratures. s. Bios Biosci ci Biot Biotechno echnoll Bioch Biochem em 1997;6 1997;61:138 1:138– –45. [84] Ndo NdoyeB, yeB, Leb Lebecq ecque ue S,Dubois S,Dubois-Da -Dauph uphin in R, Tou Tounka nkara ra L, Gui GuiroAT, roAT, Ker Kere e C, Dia Diawar wara a B, Thona Thonart rt P. Therm Thermores oresistan istantt prope properties rties of aceti aceticc acids bacte bacteria ria isola isolated ted from trop tr opic ical al pr prod oduc ucts ts of Su Subb-Sa Saha hara ran n Af Afri rica ca an and d de dest stin ined ed to in indu dust stri rial al vin vineg egar ar.. Enzyme Enzym e Microb Techn Technol ol 2006; 2006;39:916 39:916– –23. [85] Ma Mats tsut utan anii M, Ni Nish shik ikur ura a M, Sai aich chan ana a N, Hat atan ano o T, Ti Tipp ppay ayas asak ak UM UM,, Gun jana Theergool G, Yakushi T, Matsushita K. Adaptive mutation of Acetobacter pasteurianus SKU SKU1108 1108 enh enhanc ances es ace acetic tic aci acid d fer fermen mentat tation ion abil ability ity at hig high h tem tem-perature. perat ure. J Biote Biotechnol chnol 2013;1 2013;165:109 65:109– –19. [86] Soem SoempholW, pholW, Deer DeeraksaA, aksaA, Matsu MatsutaniM, taniM, Yak Yakush ushii T,Toyam T,Toyama a H,Adach H,Adachii O, Yamada M, Mat Matsus sushit hita a K. Glo Global bal ana analys lysis is of thegenesinvol thegenesinvolved ved in thetherm thethermoto otoler leranc ance e mechanismof thermotoleran thermotolerantt Acetobactertropicalis SKU1100. BiosciBiotechnol Biochem Bioch em 2011;7 2011;75:1921 5:1921– –8.
