氧化葡萄糖酸杆菌发酵L-山梨糖工艺

Efficient Production of L-Sorbose by Gluconobacter oxydans

摘要:

为了实现L-山梨糖的高效生产，利用代谢改造的手段构建获得一株过量表达山梨醇脱氢酶基因（sldhAB）的重组菌氧化葡萄糖酸杆菌（Gluconobacter oxydans SLDH）。利用海藻酸钠和硅藻土包埋法固定化细胞，并在1 L发酵罐中对发酵条件和补料策略进行了优化，通过对发酵过程中底物消耗进行数学模拟，最终建立了分批补料发酵工艺。研究发现，和野生菌相比，在1 L发酵罐水平上重组菌L-山梨糖的产量提高了20.3%，且发酵周期缩短了1/3以上。利用固定化重组菌进行分批补料发酵可完成19 d的补料发酵，其L-山梨糖净累积量比野生菌提高了30.3%。

Abstract:

In order to achieve more efficient production of L-sorbose from D-sorbitol by Gluconobacter oxydans WSH-003, an engineered strain G. oxydans SLDH with overexpressed sorbitol dehydrogenase gene sldhAB was constructed. Effect of immobilized cells on a combination carrier of sodium alginate and diatomite to produce L-sorbose was investigated. Feeding strategies of immobilized fermentation were optimized in 1-L fermentor. A fed-batch fermentation model was established based on the kinetic model of D-sorbitol consumption in batch fermentation. By self-overexpressing the sldhAB gene in G. oxydans, the yields of L-sorbose increased by 20.3% while the fermentation time was shortened by 1/3 compared to the control strain in 1-L fermentor. Besides, the L-sorbose yield was raised by 30.3% using the fed-batch fermentation with a 19 days fermentation period in a bioreactor.