面向三羟基雄甾烯酮的生物转化,选择合适的方法和材料对亚麻刺盘孢霉Colletotrichum lini ST-1进行固定,随后考察了固定化条件、转化条件和重复利用批次对固定化细胞的影响。结果表明,以海藻酸钠(SA)包埋的方法较为合适。优化的固定化条件为:SA 30 g/L,CaCl250 g/L;转化去氢表雄酮(DHEA)的最佳条件为:温度27℃,转速180 r/min,缓冲液浓度20 mmol/L,12 g固定化小球/20 mL缓冲液,添加11 mmol/L FeSO4、90 g/L甘油和20 g/L PEG。在该条件下进行生物转化,产物摩尔得率为68.7%,较游离细胞(51.2%)提高34.1%幅度。批次转化结果显示,底物最佳添加量为10 g/L。此时,固定化细胞可重复使用4批次,产能为1.09(g产物/g细胞),为游离细胞的3倍。

Take the yield of 3β,7α,15α-trihydroxy-5-androsten-17-one( 7α,15α-diOH-DHEA) as index,suitable methods and materials for the immobilization of Colletotrichum lini ST-1( C. lini ST-1) were selected. Then,the impact of immobilization conditions,conversion conditions and reused batches on immobilized cells were investigated. The results showed that,cells entrapted in sodium alginate( SA) were proved to be more appropriate,and the optimized immobilization conditions were SA 3%( m /v) and CaCl25%. The optimum transformation conditions of dehydroepiandrosterone( DHEA) by immobilized cells were as follows: temperature 27 ℃,shaker speed 180 r /min,buffer concentration 20 mmol /L,12 g of immobilized beads /20 mL buffer solution,addition of 11 mmol /L glycerol,9% FeSO4and 2% PEG400. On above condition,when 8 g /L DHEA was added,the yield of the product were up to71. 2%,increased 47. 5% compared with using free cells. Batch conversion results showed that the best concentration of substrate was 10 g /L. At the same time,the immobilized cells could be reused for 4 batches. The capacity of the immobilized cells was 1. 09( g product /g cells),which was 2 times higher than that of free cells.