Construction of efficient yeast cell factories for production of ginsenosides precursor dammarenediol-II / 药学学报

ABSTRACT

Dammarenediol-Ⅱ is an important precursor in the biosynthesis pathway of ginsenosides which are the main active components of Panax quinquefolius and Panax ginseng. For constructing a dammarenediol- Ⅱ-producing cell factory, the triterpenoid precursors of yeast are improved significantly by the modular pathway engineering strategy on the basis of an MVA optimized strain. The strain overexpressing Salvia miltiorrhiza SmFPS and Arabidopsis thaliana AtSQS2 could yield 67.4 mg·g−1 squalene, accounting for about 6.74% of cell dry weight. In our further work, an Arabidopsis thaliana 2,3-oxidosqualene synthase AtSQE2 was found to be able to increase the downstream lanosterol yield by 22-fold, reaching 47.9 mg·g−1. Then, regulating dammarenediol-Ⅱ synthase gene expression, using anti-sense RNA technology for regulation of ERG7 in the ergosterol pathway, and optimizing fermentation process were successively performed. Finally, the synthesis flux of triterpenes was increased to 10 g·L−1 for the first time, and we constructed an efficient cell factory that can produce 15 g·L−1 dammarenediol-Ⅱ, which lays a solid foundation of industrial synthesis of dammarane-type ginsenosides.