大肠杆菌角鲨烯合成途径的构建与调控

Construction and regulation of squalene synthesis pathway in Escherichia coli

角鲨烯因其具有良好的抗氧化功能而被广泛应用于食品、医药、化妆品、工业应用等领域。本实验在大肠杆菌中构建角鲨烯合成途径,通过对其合成途径中关键限速酶(1-脱氧-D-木酮糖-5-磷酸合酶和异戊烯基二磷酸异构酶)过表达的方法进行初步调控,使角鲨烯的产量提升了近三倍。之后采用单因素试验对其发酵培养基和培养条件进行优化,以此来提高角鲨烯的产量。优化发酵条件后,使用最优发酵培养基——TB培养基,在最佳发酵条件:37℃,220r/min培养至OD600约为1.2时加入终浓度为0.1mmol/L的IPTG诱导剂,25℃条件下诱导48h,角鲨烯产量可达73.88mg/L。

Squalene is widely used in food, medicine, cosmetics, industrial applications and other fields because of its good antioxidant function. In this experiment, the synthetic pathway of squalene was constructed in E. coli , and the over-expression of the key rate-limiting enzymes (1-deoxy-D-xylulose 5-phosphate synthase and isopentenyl diphosphate isomerase) in its synthesis pathway was preliminarily regulated, which nearly tripled the production of squalene. Then the fermentation medium and culture conditions were optimized by single factor experiment in order to improve the yield of squalene. After optimizing of the fermentation conditions, the optimal fermentation medium, TB medium, was used. The optimum fermentation conditions were as follows:cultured at 37 ℃ and 220 r/min, until OD 600 was about 1.2, IPTG inducer with final concentration of 0.1 mmol/L was added, and induced at 25 ℃ for 48 h. As a result, the yield of squalene was as high as 73.88 mg/L.