三羟基雄甾烯酮高转化菌株的选育及工艺优化

Breeding of high 3β,7α,15α-trihydroxy-5-androsten-17-one transforming strains and their conversion process optimization

以能将去氢表雄酮(DHEA)转化为三羟基雄甾烯酮(7α,15α-diOH-DHEA)的赤霉菌Gibberella intermedia CA3-1为出发菌株,对其进行了诱变选育及工艺优化,以期提高转化效率。采用0.12 mg/mL亚硝基胍诱变处理赤霉菌孢子悬液30 min,以350μmol/L酮康唑为最低抑制浓度进行抗性平板筛选,最终获得一株遗传稳定性较好的高产菌株M-10,其产物摩尔得率达到70.2%,为出发菌株的1.2倍。通过摇瓶转化工艺的优化,确定了突变菌株的最适转化工艺。在优化的转化工艺下,当底物DHEA投料浓度为5 g/L时,7α,15α-diOH-DHEA摩尔得率提高到75.6%,较原始菌株提高了31.3%。

In order to improve transformation efficiency of dehydroepiandrosterone （DHEA） into 3β,7α,15α-trihydroxy- 5-androsten-17-one （7α, 15α-diOH-DHEA） by Gibberella intermedia CA3-1, we investigated the strains breeding and their conversion process optimization. G. intermedia CA3-1 strains were treated with 0.12 mg/mL 1-methyl-3-nitro-l-nitroso-guanidin （NTG） for 30 rain and chosen by 350 gmol/L minimum inhibitory concentration ketoconazole resistance marker. The high production strain named M-10 with a good genetic stability was selected and the product molar yield achieved to 70.2%,which was 20% higher than that of original strain. Under the improved conversion process with the DHEA concentration of 5 g/L, the product molar yield of the mutant M-10 reached 75.6%, which was improved by 31.3% than that of original strain.