高密度发酵重组大肠杆菌产海藻糖合成酶

High cell density cultivation of Escherichia coli for the production of trehalose synthase

酶法催化是目前生产海藻糖的主要手段。本文中,笔者通过高密度发酵重组大肠杆菌产海藻糖合成酶,进而以麦芽糖为底物,催化生产海藻糖。首先根据大肠杆菌高密度发酵条件要求,在揺瓶中对基因工程菌进行了培养基、发酵条件和诱导条件的逐一优化;然后在5L和50L发酵罐中进行批次补料发酵的放大实验;最后采用变指数恒pH法的策略发酵重组大肠杆菌,结果OD600达到97,海藻糖合成酶酶活达到(24000±350)U/mL,实现了海藻糖合成酶的重组大肠杆菌高密度发酵生产,极大提高了海藻糖的生产效率。

Enzymatic catalysis is the main process for the trehalose production.In this study,we used high cell density cultivation of recombinant Escherichia coli to produce trehalose synthase and synthesized trehalose using maltose as a substrate.Firstly,according to conditions of high cell density culture of E.coli,we optimized the culture medium,fermentation conditions and induction conditions for producing trehalose synthase.Then,the scale-up experiments of fed-batch fermentation were conducted in 5 L and 50 L fermentors.Finally the fed-batch fermentation strategy-changed exponential-pH-stat feeding was carried out to produce trehalose synthase.The cell density and enzyme activity was 97 (OD600) and (24 000±350) U/mL,respectively,which greatly improved the production efficiency of trehalose.