title: Overexpression of afsR and Optimization of Metal Chloride to Improve Lomofungin Production in Streptomyces lomondensis S015.
abstract: As a global regulatory gene in Streptomyces, afsR can activate the biosynthesis of many secondary metabolites. The effect of afsR on the biosynthesis of a phenazine metabolite, lomofungin, was studied in Streptomyces lomondensis S015. There was a 2.5-fold increase of lomofungin production in the afsR-overexpressing strain of S. lomondensis S015 N1 compared with the wild-type strain. Meanwhile, the transcription levels of afsR and two important genes involved in the biosynthesis of lomofungin (i.e., phzC and phzE) were significantly upregulated in S. lomondensis S015 N1. The optimization of metal chlorides was investigated to further increase the production of lomofungin in the afsR-overexpressing strain. The addition of different metal chlorides to S. lomondensis S015 N1 cultivations showed that CaCl2, FeCl2, and MnCl2 led to an increase in lomofungin biosynthesis. The optimum concentrations of these metal chlorides were obtained using response surface methodology. CaCl2 (0.04 mM), FeCl2 (0.33 mM), and MnCl2 (0.38 mM) gave a maximum lomofungin production titer of 318.0 ± 10.7 mg/l, which was a 4.1-fold increase compared with that of S. lomondensis S015 N1 without the addition of a metal chloride. This work demonstrates that the biosynthesis of phenazine metabolites can be induced by afsR. The results also indicate that metal chlorides addition might be a simple and useful strategy for improving the production of other phenazine metabolites in Streptomyces.
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Huasheng
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Huasong
authors.initials: H
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Xuehong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001709:Biotechnology; D049109:Cell Proliferation / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D008670:Metals / Q000494:pharmacology; D010619:Phenazines / Q000032:analysis / Q000378:metabolism*; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002712:Chlorides; D004268:DNA-Binding Proteins; D008670:Metals; D010619:Phenazines; D014157:Transcription Factors; C100203:lomofungin