Efficient biosynthesis of antitumor ganoderic acid HLDOA using a dual tunable system for optimizing the expression of CYP5150L8 and a Ganoderma P450 reductase.

Ganoderic acid 3-hydroxy-lanosta-8,24-dien-26-oic acid (GA-HLDOA), an antitumor triterpenoid from the traditional Chinese medicinal higher fungus Ganoderma lucidum, is considered as a key precursor for biosynthesizing other ganoderic acids (GAs) with superior antitumor activities. Our previous study identified CYP5150L8 from G. lucidum as a lanosterol oxidase, and achieved heterologous biosynthesis of GA-HLDOA in Saccharomyces cerevisiae. However, low production of GA-HLDOA in either G. lucidum or heterologous host hindered its further investigation and application. In this study, we constructed a dual tunable system for balancing the expression of CYP5150L8 and a Ganoderma P450 reductase iGLCPR, and performed a comprehensive optimization of CYP5150L8 expression, iGLCPR expression, and glycerol usage. Then, we investigated the fermentation behavior of the best strain in optimized condition in flask and achieved 154.45 mg/L GA-HLDOA production, which was 10.7-fold higher compared with previous report. This study may facilitate the wide-spread application of GA-HLDOA and the discovery of unknown cytochrome P450s in downstream GAs biosynthesis.