Abstract

A glycosyltransferase for efficiently converting p HBA into gastrodin was screened. • Enhancing UDP-glucose supply can significantly increase the gastrodin titer in E.coli . • Combinatorial optimization achieved 4578.03 mg/L gastrodin in engineered E. coli . Gastrodin is the principal bioactive component of Gastrodia elata , which is famous for its many remarkable pharmacological properties. In this study, several UDP-glycosyltransferases from different sources were used to evaluate and compare the biotransformation ability of p -hydroxybenzyl alcohol to gastrodin. The recombinant strain BL-RrUGT, expressing the UDP-glycosyltransferase (RrUGT) from Rhodiola rosea , exhibited the highest initial titer of 210.60 mg/L. To further augment production, we enhanced the intracellular UDP-glucose level in Escherichia coli ( E. coli ) K12 by overexpressing two pivotal biosynthetic enzymes: phosphoglucomutase and UDP-glucose pyrophosphorylase. This metabolic engineering strategy yielded the recombinant strain BL-Rr-PG, which boosted the gastrodin titer to 342.40 mg/L. Subsequently, the culture medium and fermentation conditions were optimized. This resulted in a maximum gastrodin titer of 4578.03 mg/L, with a specific productivity of 69.36 mg/L/h and a molar conversion rate of 82.72%. This output represents the highest yield of gastrodin reported in E. coli to date. Download: Download high-res image (198KB) Download: Download full-size image