• Title/Summary/Keyword: Poly(ε-ʟ-lysine)

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Construction of a Genetic System for Streptomyces albulus PD-1 and Improving Poly(ε-ʟ-lysine) Production Through Expression of Vitreoscilla Hemoglobin

  • Xu, Zhaoxian;Cao, Changhong;Sun, Zhuzhen;Li, Sha;Xu, Zheng;Feng, Xiaohai;Xu, Hong
    • Journal of Microbiology and Biotechnology
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    • v.25 no.11
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    • pp.1819-1826
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    • 2015
  • Poly(ε-ʟ-lysine) (ε-PL) is a novel bioactive polymer secreted by filamentous bacteria. Owing to lack of a genetic system for most ε-PL-producing strains, very little research on enhancing ε-PL biosynthesis by genetic manipulation has been reported. In this study, an effective genetic system was established via intergeneric conjugal transfer for Streptomyces albulus PD-1, a famous ε-PL-producing strain. Using the established genetic system, the Vitreoscilla hemoglobin (VHb) gene was integrated into the chromosome of S. albulus PD-1 to alleviate oxygen limitation and to enhance the biosynthesis of ε-PL in submerged fermentation. Ultimately, the production of ε-PL increased from 22.7 g/l to 34.2 g/l after fed-batch culture in a 5 L bioreactor. Determination of the oxygen uptake rate, transcriptional level of ε-PL synthetase gene, and ATP level unveiled that the expression of VHb in S. albulus PD-1 enhanced ε-PL biosynthesis by improving respiration and ATP supply. To the best of our knowledge, this is the first report on enhancing ε-PL production by chromosomal integration of the VHb gene in an ε-PL-producing strain, and it will open a new avenue for ε-PL production.