代谢工程改造大肠杆菌生产水杨酸葡萄糖苷

Metabolic engineering of Escherichia coli for production of salicylate 2-O-β-d-glucoside

摘要:

水杨酸葡萄糖苷(salicylate 2-O-β-d-glucoside,SAG)，是植物中水杨酸的一种存在形式。水杨酸葡萄糖苷也具有消炎止痛的作用，和水杨酸、阿司匹林对比，表现出更小的刺激性，是一种具有潜力的消炎护肤物质。通过生物法利用可再生资源进行水杨酸类物质的生产方式，与传统工业法生产相比对环境更加友好。本研究以大肠杆菌(Escherichia coli) Tyr002作为出发菌株，引入铜绿假单胞菌(Pseudomonas aeruginosa)异分支酸裂解酶基因pchB，首先构建了大肠杆菌水杨酸生产菌株。通过调控下游不同芳香族氨基酸代谢途径关键基因表达，菌株摇瓶发酵水杨酸产量达到1.05 g/L。之后，通过在水杨酸生产菌株中引入植物来源水杨酸糖基转移酶，对水杨酸进行糖苷化修饰。新构建的菌株摇瓶发酵水杨酸葡萄糖苷产量达到5.7 g/L。在5 L发酵罐分批补料发酵中，水杨酸葡萄糖苷的产量达到36.5 g/L，是目前报道的最高产量。本研究为水杨酸类化合物的微生物合成提供了重要参考。

Abstract:

Salicylate 2-O-β-d-glucoside (SAG) is a derivative of salicylate in plants. Recent reports showed that SAG could be considered as a potential anti-inflammatory substance due to its anti-inflammatory and analgesic effects, and less irritation compared with salicylic acid and aspirin. The biological method uses renewable resources to produce salicylic acid compounds, which is more environmentally friendly than traditional industry methods. In this study, Escherichia coli Tyr002 was used as the starting strain, and a salicylic acid producing strain of E. coli was constructed by introducing the isochorismate pyruvate lyase gene pchB from Pseudomonas aeruginosa. By regulating the expression of the key genes in the downstream aromatic amino acid metabolic pathways, the titer of salicylic acid reached 1.05 g/L in shake flask fermentation. Subsequently, an exogenous salicylic acid glycosyltransferase was introduced into the salicylic acid producing strain to glycosylate the salicylic acid. The newly engineered strain produced 5.7 g/L SAG in shake flask fermentation. In the subsequent batch fed fermentation in a 5 L fermentation tank, the titer of SAG reached 36.5 g/L, which is the highest titer reported to date. This work provides a new route for biosynthesis of salicylate and its derivatives.