Enhanced ε-poly-l-lysine production by inducing double antibiotic-resistant mutations in Streptomyces albulus
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- 作者：Liang Wang ; Xusheng Chen ; Guangyao Wu ; Shu Li…
- 关键词：Streptomyces albulus FEEL ; 1 ; Key enzyme activities ; qRT ; PCR ; Ribosome engineering ; Double drug ; resistant mutation
- 刊名：Bioprocess and Biosystems Engineering
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：40
- 期：2
- 页码：271-283
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Biotechnology; Industrial and Production Engineering; Environmental Engineering/Biotechnology; Industrial Chemistry/Chemical Engineering; Food Science;
- 出版者：Springer Berlin Heidelberg
- ISSN：1615-7605
- 卷排序：40
文摘
ε-Poly-l-lysine (ε-PL), as a food additive, has been widely used in many countries. However, its production still needs to be improved. We successfully enhanced ε-PL production of Streptomyces albulus FEEL-1 by introducing mutations related to antibiotics, such as streptomycin, gentamicin, and rifampin. Single- and double-resistant mutants (S-88 and SG-31) were finally screened with the improved ε-PL productions of 2.81 and 3.83 g/L, 1.75- to 2.39-fold compared with that of initial strain FEEL-1. Then, the performances of mutants S-88 and SG-31 were compared with the parent strain FEEL-1 in a 5-L bioreactor under the optimal condition for ε-PL production. After 174-h fed-batch fermentation, the ε-PL production and productivity of hyper-strain SG-31 reached the maximum of 59.50 g/L and 8.21 g/L/day, respectively, which was 138 and 105% higher than that of FEEL-1. Analysis of streptomycin-resistant mutants demonstrated that a point mutation occurred in rpsL gene (encoding the ribosomal protein S12). These single and double mutants displayed remarkable increases of the activities and transcriptional levels of key enzymes in ε-PL biosynthesis pathway, which may be responsible for the enhanced mycelia viability, respiratory activity, and ε-PL productions of SG-31. These results showed that the new breeding method, called ribosome engineering, could be a novel and effective breeding strategy for the evolution of ε-PL-producing strains.