Fctl-bltch culturc is rccognizcd its it po\\crful ttxrl for orcrcrlrlrirrg .... BATCH AND FED.BATCH SOLID-STATE FERMENTATIONS t.6 0 o. = o t't. CD. E o o. E .9.
BATCH AND FED-BATCHSOLD.STATE FERMENTATIONS:KINETICS OF CELL GROWTH, HYDROLYTIC ENZYMESPRODUCTION.ANI) GIBBERELLIC ACID PRODUCTION By P. K. R. KUMAR and B. K. LONSANE lclcn honc: 116(rl l :l cl cr: N l () 11l . S Y N OP S IS In a I'ed-batchsolid-slateli'rnrentation inrolring lhe l'eedingofcorn slarch during idiophase. the rate and the quantities of produclion rtf gibberellic acid. drl crll mass. and protcases prrduced uerc highcr lhan those in batch solid-state l'trnrenlation. uhilst the ralues lirr amr'lascs.cellulases.and rllanascs uere louer. Pectinases*ere ahsent in hoth the s.lstemsand parlial inhihilion ol gihherellic acid formation rrccurred nith f'eedpoliciesinrolving moist wheat-hran medium or glucose as compared lo corn slarch. 'l'hc results indicale lhe conrpler nature of thc biochemical changes during thr prrduclion of gibberellic acid under hatch and l'ed-batchsolid-slatefermenlations.
Introduction F ccl-b ltch cu lturc. r lr iahlr c ulled s c r ni- hat c h. or r crtcndcrl lrirrclrcrrlfu rc.' hls I c c c r t tlr gc r r c nr t c tsl or lt l- u ir lc ir r t c r c s t . ' It involrcs a fcrnrcntcr 0pcrati0n-striltegvbirse(l()n con\ t an l ()r intcrrlitten t f c c t l : t r eanr s . lr nd c ont uir r nr c n l( ) f t h c proclu ctin th c fcrn tc nt c r up t ( ) t he c nd of t he r un. ' Fc tl - b l t c h culturc is rccognizcd its it po\\crful ttxrl for orcrcrlrlrirrg screrirl rcrlrictiorrs tln fernrcntltion cfficicncr,.suclr ls strhstrutc in hib ition . cu t ul' r olicr epr c \ s i( ) lt . high c ' c ll c ( ) n c e n t n l tion. und glucosccffect. lt also proviclesun efticientnroclelor the crtcnsiorrof thc prorluctirlnphuse. rcplaccntcnt()f \\'ittcr I ost bl crlp or;.rtitlrr.lnr l f t r r r lc c r eas ingv i; c os it r of hr o t h . 'I n adclitio n.it ulkxrs volur r t lr r c ont r ol of t hc , : onc c r r t r l t i o n r l f nutricnts fctl into th c f er nr ent c r ' hv . c hunginqt he f c c d r : r t c : ' t his is no t po ssitrlcin bat c irc ult ur c . F ttl-ha tch cultu rc has bc c or nc a nlr jor dc r c lopn r e n t i n ferrncntationtcchlt()l()gllnrl hls bccn successfullr' .'xploitctl contntcrcilrllr."ntitinlv trccauseol srrehlrtlrarrtltgcsls c:rscrlf tlpcr:rtion lrntl hiqhcr procluctirin us conrparctlto thc continuor rscu lture tcclrni quc . r LIntil rccen tl). thc f c t l- blt c h c ult ur c u' as c onlir r edt ( ) s u b nrcrgctl fcrn tcrttltio n * it h t he c \ c c pt i( ) n of it s s uc c e s s f u l lpplicltion trr tlrc so lid- s t at ct er nr ent at ion( SSF) t c c h n i q u c t irr thc pro du ctio n o l s ihhc r ellic lc id ( G A, ) . - Thc d i s t u r hanccs in th c' a ttachnt ent of c ells t o r r hc at br an ( WB ) plrtic lcs ncccssitutcdbec aus cof t he nr ix ing t lf int c r n r i t t c r r t leet l u ith n toist solid s undc r goingt er r nc nt at ir ln.uer c t i l u n d to have no cfti'ct on C;Ar productivit\'. Thc procc-ss uas llscr ahlc to ()\'crconrcsubstratcinhibition bv solublc starch thcrcbv lca clin gto an in rpr ov enlc ntin t hc \ ir ' ld ol G A, hr l f i . l " r , as conrparcclto lhe conl'entionalbltch SSF procc:s.With a view to cxplt)rinqthe possibilitvof further intprovemcnts in thc riclcl of G A, . dif f er c nt f eed polic ie s u e r e evalu ate d. In tdd ition. t he c onr par at iv e k inc t ic s o f c e l l growth. h 1'd roll'tice nz v m es . and G Ar pr oduc t ion d u r i n u batch and t'cd-butchSSF nrocesscswerc studied to tind out their rolc in inrprovcd productivitv in thc ted-bltch SSF proccss. The results of these studies arc reported in thc prescntcontmunicationas thcse arc not ilvailablein litcrature on ti'd-batch culture in SSF and subntergcclfermentation techniq ues.
cortrluctcrltsicc antl clch \\'ls pcrlirrrncclin triplicltc. T h c a v e r i r g cr a l u e s a r c r e p o r t c d a s t h e v a r i u n c csi n th c r t 's t r l t ss c r c b s s t h a n + 6 " , , . Rtt
1.50
a U o c XE
z6 -a
z9
0.50
6e o E
L
INCUBAT ION PERIOD(h)
INCUBATIONPERIOD(h)
T h e ra te o f o ro d u ction of cellulases based on biomass is c al c ul ated fr om b i o ma ss va l u e s repor ted in Figur e 3.
]l : batch SSF process tII! : fed-batchSSF orocess SSF= solid-statefermentation GA3= gibberellicacid D M8=dry moul dy bran The rate of productionof xylanasesbasedon biomass is calculatedfrom biomass values reported in Figure 3.
J'i q u re 5 : l -crcl untl nr lc ol lir r r r r ir tion ol cellullscs in batc h and l c dh i rtcl rcs so l i tl -sti ltc lcnncntlr li( ) ns I( ) r the nr otluctior r ol !:i l .bc r c l l i c i tcl 0 .
F'igure 6: Anr()unt and ratc of ftrrmation of xylanascs in batch and Icd-hatch solid-statc' fcrmcntation processesfor the production of gi htrcrcl l i caci cl .
: b a tch S S F p rocess I@ : fe d -b a tch SSF pr ocess S S F so l i C-sta te fer m entation GA , g i b b e re l l i c acid DMB d ry mo u l d y br an
tritst. thc riltL' ()f procluction of totul ccllulases(hascclon lrionrlss) incrclsed up t() l-l-l hours and then decreasecl. llos'crcr. thc ratcs h:rsed on DMB increasedup to l-l-l h ou rs lnrl th cn r c r nuinet lc ons t antup t o l9: ho u r s . ()n thc othcr huncl. the amount ancl rilte of production of \\'llnasc\ incrcused$ith t'ermentationtime up to 192hours in hoth thc pr()cesscs(Figurc (r). Howcvcr. in t'ed-batchSSF pr()ccssthcse riltcs ilre neurlv half of those for batch SSF pr()ccss. Thc inhibition of thc production of cellulasesin Fusuriurtr so/arri bl' GA, is known.r' Thcrefore the lower level of ccllullses in fecl-batchSSF prclcessmirv either be rc'latedto thcir inhibition hv incrcascdlevel of GA, or the restrictionof their forrnation. The presenceof cellulasesin batch ilnd fedbatch SSF pr()ccsscs llso indicatessimultilncoushydrolysisof starch a nd ce llulos c . Thcsc comnrcnts mav also be relevant to xvlanases.Thc cclluklscs und pcntosans constitute maj()r c()mponents of WB atnourrting to 22 and 2-5'2,of drv WB respL.ctivclv.r" The levcls of total ccllulasesand xvlanases.even in batch SSF pr()ccss. lre much lower than those in
