过量表达枯草芽孢杆菌乙偶姻还原酶提高2,3-丁二醇产量

Improved 2,3-Butanediol Production by Overexpressing Acetoin Reductase in Bacillus subtilis 168

摘要:

枯草芽孢杆菌Bacillus subtilis 168是一株安全生产的菌株，但是在2，3?鄄丁二醇（2，3-BD）的发酵过程中，会积累较多的副产物乙偶姻（AC）。乙偶姻还原酶是催化AC合成2，3?鄄BD的关键酶。为了提高2，3-BD合成效率，首先将乙偶姻还原酶基因acr克隆到B. subtilis 168，构建了重组菌B. subtilis 168/pMA5-acr。对重组菌进行摇瓶发酵实验，结果表明，相比出发菌，重组菌的2，3-BD产量和转化率分别提高28.62%和22.87%，主要副产物AC积累量下降了20.01%。同时，分支路径的副产物甲酸、乙酸、乳酸、琥珀酸，也有不同程度的降低。

Abstract:

Bacillus subtilis 168 is a safe strain for industrial-scale microbial production of 2，3-butanediol （2，3-BD）. However， a large quantity of by-product of acetoin （AC） is accumulated during 2，3-BD fermentation process. acetoin reductase （ACR） is the key enzyme which catalyzes the conversion of acetoin to 2，3-BD. In this study，in order to improve 2，3-BD production，we firstly cloned the acr gene of acetoin reductase into B. subtilis 168，and then further constructed the recombinant strain B. subtilis 168/pMA5-acr. The results showed that the yield and conversion rate of the 2，3-BD were increased up to 28.62% and 22.87% by the recombinant strain，respectively. Whereas the accumulation of the main by-product of acetoin decreased by 20.01%. Furthermore，the molar yields of by-products of formic acid，acetic acid，lactic acid，and succinate were also decreased.