关键词: 紫杉二烯, 酵母底盘, 功能模块, 诱导型启动子, 组成型启动子

Abstract: In recent years,producing terpenoids in microbe by synthetic biology methods has become more and more popular.Inducible promoters and constructive promoters have both advantages and disadvantages. The choice of promoters depends on the specific systems and target compounds.In this research,regulations of heterologous modules by inducible and constructive promoters were studied respectively for the taxadiene synthesis in Saccharomyces cerevisiae.A yeast chassis was firstly constructed after expressing a truncated 3-hydroxyl-3-methylglutaryl-CoA reductase gene(thmgr),endogenous farnesyl diphosphate synthase gene(erg20)under the regulation of tdh3 promoter.After inserting the heterologous module in which ts was regulated by inducible promoter into the genome of chassis,an engineered strain which produced 5.2 mg·L^-1 taxadiene was obtained.When the promoter was replaced by constructive one-tdh3p,the yield increased to 11.5 mg·L^-1.That indicated the constructive promoter may be more suitable for the taxadiene synthesis system in yeast.After a simple fermentation optimization in shaking flask,the yield increased by 70% to reach 19.5 mg·L^-1.Strains regulated by constructive promoters can use glucose as carbon source which was suitable for large scale fermentation in future.

Key words: taxadiene, yeast chassis, functional module, inducible promoter, constructive promoter