Efficient Production Hyperoside from Quercetin in Escherichia coli Through Increasing UDP-Galactose Supply and Recycling of Resting Cell

Hyperoside is used as the standard to assess the quality of Hyperin perforatum L and exhibits many biological properties. To improve the yield of hyperoside in Escherichia coli, four UDP-galactose synthesis pathways were screened and a recombinant strain was reconstructed by using an efficient UDP-galactose generation system coupled with Petunia hybrida glycosyltransferase to biosynthesis hyperoside from quercetin. By adopting the resting cell transformation, maximal hyperoside production of 4574 mg/L and average productivity of 63.5 mg/L/h were achieved after 72 h of biotranformation. Subsequently through recycling of resting cells, average productivity within 72 h reached 126 mg/L/h, which was 100% higher than that in the batch fermentation. Hyperoside production reached equivalent to 18,000 mg/L by recycling seven times of resting cell in 168 h, which was 393% of that in the batch fermentation and the first to reach 10 g per liter scale in E. coli. Therefore, this study provides an efficient method for construction of UDP-galactose synthesis pathway and hyperoside production in E. coli.