CAJ | 학술논문

研究不同复合包埋材料对含腈水解酶的Gibberella intermedia CA3-1进行固定化，选择出最为适合的壳聚糖-聚乙烯醇作为复合包埋材料，其优化后的浓度分别为1.6%和2%。实验结果表明该固定化细胞的最适转化条件为：3-氰基吡啶初始浓度300mmol/L，转化温度30℃，pH值7.0，转化时间60min。固定化细胞可以稳定进行26个批次转化，每克干细胞可转化产生283.5g烟酸，为游离细胞的3倍。此外，固定化细胞对高浓度3-氰基吡啶的耐受性大幅提高，温度稳定性有一定增强。连续补料19次，固定化细胞酶活保留约30%，经折算产率为每克干细胞转化生成191.3g烟酸。
연구불동복합포매재료대함정수해매적Gibberella intermedia CA3-1진행고정화，선택출최위괄합적각취당-취을희순작위복합포매재료，기우화후적농도분별위1.6%화2%。실험결과표명해고정화세포적최괄전화조건위：3-청기필정초시농도300mmol/L，전화온도30℃，pH치7.0，전화시간60min。고정화세포가이은정진행26개비차전화，매극간세포가전화산생283.5g연산，위유리세포적3배。차외，고정화세포대고농도3-청기필정적내수성대폭제고，온도은정성유일정증강。련속보료19차，고정화세포매활보류약30%，경절산산솔위매극간세포전화생성191.3g연산。
Nicotinic acid biotransformation by immobilized Gibberella intermedia CA3-1 harboring nitrilase was investigated in this study. Chitosan-polyvinyl alcohol was found to exhibit great advantages over other composite materials,with contents of chitosan and polyvinyl alcohol 1.6%and 2%,respectively. The experimental results showed that the optimal transformation conditions were as follows:initial 3-cyanopyridine concentrations of 300mmol/L,transformation temperature of 30℃ and initial pH of 7.0. The substrate could be completely converted within 60min. Immobilized cells could be reused for up to 26 batches as compared to 9 batches for free cells. And 283.5g nicotinic acid/(g dcw) was produced with 80.55% enzyme activity preserved. Its transformation capability was three times higher than that of free cells. In addition,the immobilization substantially enhanced its tolerance toward high 3-cyanopyridine concentration and improved its thermalstability. Immobilized cells could biosynthesize 191.3g nicotinic acid/(g dcw),retaining 30%enzyme activity by 19 fed-batches.