生物表面活性剂Surfactin生产菌株的定向改造策略

表面活性素(Surfactin)是芽胞杆菌属(Bacillussp.)代谢产生的脂肽类生物表面活性剂,是由非核糖体肽合成酶(NRPS)催化而得的一种次级代谢产物。由于surfactin具有稳定性好、可被降解、表面活性好等理化性质以及抑菌、抗肿瘤等生物活性,在医药、农业、食品、化妆品、石油开采等方面都具有很大的应用潜力。但是,天然菌株产率低、生产成本高等特点限制了surfactin的规模化应用。本文对surfactin的合成机理进行了简要阐述,并针对目前提升surfactin产量和改变结构组分的4种定向改造策略(启动子工程、强化外排分泌、改造NRPS结构域和脂肪酸链合成酶系)进行了综述,最后对surfactin的研究方向进行了展望。

Directed modification of strains for surfactin production

Surfactin, a lipopeptide biosurfactant produced by Bacillus strains, is one of the most surface-active biosurfactant. It is assembled by nonribosomal peptide synthetases (NRPSs) as secondary metabolites in microorganism. Due to its good stability, biodegradability and excellent surface activity in extreme environments, surfactin is gaining increasing attention as a valuable chemical with great potential in medicine, agriculture, food, cosmetics and microbial enhanced oil recovery. However, the low yields and high production costs of natural strain largely limit the large-scale industrial applications of surfactin. This article briefly summarizes the mechanism for surfactin biosynthesis, and reviews the main strategy for improving the yield and changing structure of surfactin including promoter engineering, enhancing efflux system, modifying NRPS domain and engineering fatty acid synthetases. At last, we discussed the prospect of the research on surfactin in the future.