摘要
Streptomyces are the well-known producers of biologically active pharmaceuticals and agricultural antibiotics.However,the production of the secondary metabolites was limited due to the unbalance of the cell growth and the activation of secondary metabolic pathway.Here,in order to improve the production of toyocamycin,a nucleoside antibiotic produced by Streptomyces diastatochromogenes 1628,with excellent antimicrobial characteristics to plant pathogens,we develop an endogenous non-inducer-dependent dynamic regulatory strategy based on the quorum sensing(QS)promoter to fine-tune the expression of an important signal molecule(ppGpp).Firstly,two QS promoter PstbA1 and PstbA2 were identified by the bioinformatic analysis.Then,the temporal profiles of PstbA1 and PstbA2 were characterized by the GusA activity.Afterwards,the ppGpp synthase was expressed under the PstbA1 and PstbA2 to improve the ppGpp concentration in vivo.The toyocamycin production reached 768.62 mg/L and 721.06 mg/L under the QS promoter PstbA1 and PstbA2,respectively,which represented increases of 508.81%and 471.14%over the wild-type at the tenth day.The autoregulated QS-based strategy is an effective method by balancing bacterial growth and metabolite synthesis in industrial processes.
基金
funded by the National Natural Science Foundation of China(32372628)
the Fundamental Research Funds for the Provincial Universities of Zhejiang(2022YW17)。
