重组大肠杆菌催化橙皮素合成新橙皮苷

Production of neohesperidin from hesperetin by an engineered strain of Escherichia coli

新橙皮苷是一种黄酮糖苷,广泛应用于食品和药品行业。目前新橙皮苷生产主要通过植物提取法,需要大量的有机溶剂,而生物转化法绿色环保、转化率高,具有较高的经济效益。本研究在大肠杆菌中引入拟南芥来源的糖基转移酶UGT73B2、葡萄来源的鼠李糖合酶VvRHM-NRS和柚子来源的鼠李糖转移酶Cm1,2RhaT,构建了新橙皮苷的生物合成路径。通过模块优化和糖基供体强化后,重组菌株在5 L发酵罐中合成新橙皮苷的产量达到4.64 g/L,底物橙皮素的摩尔转化率为45.8%,这是目前报道的微生物中异源合成新橙皮苷的最高产量。本研究为新橙皮苷高产菌株的构建与应用奠定了基础,也为代谢工程改造微生物生产其他黄酮糖苷提供了借鉴。

Neohesperidin is a flavonoid glycoside widely used in the food and pharmaceutical industries.The current production of neohesperidin mainly relies on extraction from plants.Microbial fermentation demonstrates a promising prospect as an environmentally friendly,efficient,and economical method.In this study,we designed and constructed the biosynthetic pathway of neohesperidin in an Escherichia coli strain by introducing the glycosyltransferase UGT73B2 from Arabidopsis thaliana,rhamnose synthase VvRHM-NRS from Vitis vinifera,and rhamnose transferase Cm1,2RhaT from Citrus maxima.After optimization of the module and the uridine diphosphate(UDP)-glucose synthetic pathway,the engineered strain produced 4.64 g/L neohesperidin in a 5 L bioreactor,and the molar conversion rate of hesperetin was 45.8%.This has been the highest titer reported to date for the biosynthesis of neohesperidin in microorganisms.This study lays a foundation for the construction and application of strains with high yields of neohesperidin and provides a potential choice for the microbial production of other flavonoid glycosides.