재조합 탄산무수화 효소 첨가 생산배지를 이용한 Actinobacillus succinogenes 유래의 숙신산 생산성 향상

초록

Succinic acid, a representative biomass-derivedplatform chemical, is a major fermentation product of Actinobacillussuccinogenes. It is well known that carbon dioxide isconsumed during the succinate fermentation, but the biochemicalmechanism behind this phenomenon is not yet understoodwell. In this study, it was found that the addition of carbonicanhydrase (CA)s into media significantly enhances thesuccinic acid production by A. succinogenes during the fermentationsupplied with carbon dioxide. It is likely that the(bi) carbonate produced by the CA activity from gaseous carbondioxide is favoured by A. succinogenes for consumptionand utilization. Therefore, the MgCO3 requirement could besignificantly reduced without compromising the succinate productivity. Furthermore, because of too high price of the commercialcarbonic anhydrase, it was undertaken to economicallyoverproduce a cyanobacterial carbonic anhydrase by theuse of a recombinant Pichia pastoris. An expression vectorsystem was constructed with the carbonic anhydrase genePCR-cloned from Cyanobacterium Synechocystis sp., andintroduced into P. pastoris for fermentation studies. About95.9 g/L of succinic acid was produced in the production mediumwith 30 ppm of carbonic anhydrase, approximately 2 foldhigher productivity compared to the parallel process with nosupplementation of the enzyme. It is expected that this methodcan provide a valuable way of overcoming inefficienciesinherent in gas supply during CO2-based bioprocesses likesuccinic acid fermentation.

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