Abstract
BACKGROUND: The natural phenolic glycoside gastrodin is the major bioactive ingredient in the well-known Chinese herb Tianma and is widely used as a neuroprotective medicine in the clinic. Microbial production from sustainable resources is a promising method to replace plant extraction and chemical synthesis which were currently used in industrial gastrodin production. Saccharomyces cerevisiae is considered as an attractive host to produce natural plant products used in the food and pharmaceutical fields. In this work, we intended to explore the potential of S. cerevisiae as the host for high-level production of gastrodin from glucose. RESULTS: Here, we first identified the plant-derived glucosyltransferase AsUGT to convert 4-hydroxybenzyl alcohol to gastrodin with high catalytic efficiency in yeast. Then, we engineered de novo production of gastrodin by overexpressing codon-optimized AsUGT(syn), the carboxylic acid reductase gene CAR(syn) from Nocardia species, the phosphopantetheinyl transferase gene PPTcg-1(syn) from Corynebacterium glutamicum, the chorismate pyruvate-lyase gene UbiC(syn) from Escherichia coli, and the mutant ARO4(K229L). Finally, we achieved an improved product titer by a chromosomal multiple-copy integration strategy and enhancement of metabolic flux toward the aglycon 4-hydroxybenzyl alcohol. The best optimized strain produced 2.1 g/L gastrodin in mineral medium with glucose as the sole carbon source by flask fermentation, which was 175 times higher than that of the original gastrodin-producing strain. CONCLUSIONS: The de novo high-level production of gastrodin was first achieved. Instead of chemical synthesis or plants extraction, our work provides an alternative strategy for the industrial production of gastrodin by microbial fermentation from a sustainable resource.