代谢工程改造酿酒酵母高效合成熊果酸OA北大核心CSTPCD

Ursolic acid,a pentacyclic triterpene compound with anti-inflammatory and antioxidant effects,has been widely applied in medicine,cosmetics,and various other fields.In this study,a"push-pull"metabolic engineering strategy was employed to increase the production of ursolic acid in Saccharomyces cerevisiae.Firstly,de novo biosynthesis of ursolic acid was achieved by heterologous expression and optimization of CADDS,CaCYP716A83,and HtCPR genes,resulting in 5.4 mg/L of ursolic acid.Subsequently,an expansion of the endoplasmic reticulum area was conducted to provide more adherent surface for membrane protease activity,obtaining 40.3 mg/L of ursol-ic acid.Due to multiple REDOX reactions was involved in the ursolic acid synthesis pathway,in which the NADPH was an essential cofac-tor.By enhancing the supply of NADPH,the ursolic acid titer was increased to 48.2 mg/L.Additionally,optimization of the electron transport chain and utilization of cytochrome b5 for efficient electron transfer to P450 enzyme further enhanced the electron supply,resul-ting in 74.6 mg/L of ursolic acid.Finally,by iteratively integrating these strategies including expanding endoplasmic reticulum area,en-hancing NADPH availability,and electron transport efficiency and regulating the copy number of CaCYP716A83 and HtCPR genes,the ursoilc acid production was further enhanced to 84.3 mg/L.This study offers valuable insights for the development of efficient microbial cell factories for terpenoid synthesis,serving as a reference in the field.