Dataset Information

Enhanced ?-Poly-L-Lysine Production by the Synergistic Effect of ?-Poly-L-Lysine Synthetase Overexpression and Citrate in Streptomyces albulus.

ABSTRACT: ?-Poly-L-lysine (?-PL) is a natural amino acid polymer produced by microbial fermentation. It has been mainly used as a preservative in the food and cosmetics industries, as a drug carrier in medicines, and as a gene carrier in gene therapy. ?-PL synthase is the key enzyme responsible for the polymerization of L-lysine to form ?-PL. In this study, the ?-PL synthase gene was overexpressed in Streptomyces albulus CICC 11022 by using the kasOp? promoter and the ribosome binding site from the capsid protein of phage ?C31, which resulted in a genetically engineered strain Q-PL2. The titers of ?-PL produced by Q-PL2 were 88.2% ± 8.3% higher than that produced by the wild strain in shake flask fermentation. With the synergistic effect of 2 g/L sodium citrate, the titers of ?-PL produced by Q-PL2 were 211.2% ± 17.4% higher than that produced by the wild strain. In fed-batch fermentations, 20.1 ± 1.3 g/L of ?-PL was produced by S. albulus Q-PL2 in 72 h with a productivity of 6.7 ± 0.4 g/L/day, which was 3.2 ± 0.3-fold of that produced by the wild strain. These results indicate that ?-PL synthase is one of the rate-limiting enzymes in ?-PL synthesis pathway and lays a foundation for further improving the ?-PL production ability of S. albulus by metabolic engineering.

SUBMITTER: Wang A

PROVIDER: S-EPMC7188835 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Enhanced ε-Poly-L-Lysine Production by the Synergistic Effect of ε-Poly-L-Lysine Synthetase Overexpression and Citrate in Streptomyces albulus.

Wang Aixia A Tian Wenzhe W Cheng Lei L Xu Youqiang Y Wang Xiuwen X Qin Jiayang J Yu Bo B

Frontiers in bioengineering and biotechnology 20200422

ε-Poly-L-lysine (ε-PL) is a natural amino acid polymer produced by microbial fermentation. It has been mainly used as a preservative in the food and cosmetics industries, as a drug carrier in medicines, and as a gene carrier in gene therapy. ε-PL synthase is the key enzyme responsible for the polymerization of L-lysine to form ε-PL. In this study, the ε-PL synthase gene was overexpressed in Streptomyces albulus CICC 11022 by using the kasOp∗ promoter and the ribosome bin ...[more]

PMID: 32391338

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Project description:BackgroundAdpA is a global regulator of morphological differentiation and secondary metabolism in Streptomyces, but the regulatory roles of the Streptomyces AdpA family on the biosynthesis of the natural product ε-poly-L-lysine (ε-PL) remain unidentified, and few studies have focused on increasing the production of ε-PL by manipulating transcription factors in Streptomyces.ResultsIn this study, we revealed the regulatory roles of different AdpA homologs in ε-PL biosynthesis and morphological differentiation and effectively promoted ε-PL production and sporulation in Streptomyces albulus NK660 by heterologously expressing adpA from S. neyagawaensis NRRLB-3092 (adpASn). First, we identified a novel AdpA homolog named AdpASa in S. albulus NK660 and characterized its function as an activator of ε-PL biosynthesis and morphological differentiation. Subsequently, four heterologous AdpA homologs were selected to investigate their phylogenetic relationships and regulatory roles in S. albulus, and AdpASn was demonstrated to have the strongest ability to promote both ε-PL production and sporulation among these five AdpA proteins. The ε-PL yield of S. albulus heterologously expressing adpASn was approximately 3.6-fold higher than that of the control strain. Finally, we clarified the mechanism of AdpASn in enhancing ε-PL biosynthesis and its effect on ε-PL polymerization degree using real-time quantitative PCR, microscale thermophoresis and MALDI-TOF-MS. AdpASn was purified, and its seven direct targets, zwf, tal, pyk2, pta, ack, pepc and a transketolase gene (DC74_2409), were identified, suggesting that AdpASn may cause the redistribution of metabolic flux in central metabolism pathways, which subsequently provides more carbon skeletons and ATP for ε-PL biosynthesis in S. albulus.ConclusionsHere, we characterized the positive regulatory roles of Streptomyces AdpA homologs in ε-PL biosynthesis and their effects on morphological differentiation and reported for the first time that AdpASn promotes ε-PL biosynthesis by affecting the transcription of its target genes in central metabolism pathways. These findings supply valuable insights into the regulatory roles of the Streptomyces AdpA family on ε-PL biosynthesis and morphological differentiation and suggest that AdpASn may be an effective global regulator for enhanced production of ε-PL and other valuable secondary metabolites in Streptomyces.

Dataset Information

Enhanced ?-Poly-L-Lysine Production by the Synergistic Effect of ?-Poly-L-Lysine Synthetase Overexpression and Citrate in Streptomyces albulus.

Publications

Enhanced ε-Poly-L-Lysine Production by the Synergistic Effect of ε-Poly-L-Lysine Synthetase Overexpression and Citrate in <i>Streptomyces albulus</i>.

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