Effects of L-lysine and D-lysine on ε-Poly-L-lysine Biosynthesis and Their Metabolites by Streptomyces ahygroscopicus GIM8

• Published in: Biotechnology and bioprocess engineering Vol. 17; no. 6; pp. 1205 - 1212
• Main Authors: Liu Shengrong, Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology, Guangzhou, China, Wu Qingping, Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology, Guangzhou, China, Zhang Jumei, Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology, Guangzhou, China, Mo Shuping, Guangdong Institute of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, State Key Laboratory of Applied Microbiology, Guangzhou, China
• Format: Journal Article
• Language: English
• Published: 한국생물공학회 01.11.2012
• Subjects: D-lysine; epsilon-poly-L-lysine biosynthesis; L-lysine; METABOLITE; METABOLITES; METABOLITOS; STREPTOMYCES; 생물공학
• ISSN: 1226-8372; 1976-3816
• DOI: 10.1007/si2257-012-0296-7

ε-Poly-L-lysine (ε-PL), produced by Streptomyces or Kitasatospora strains, is a homo-poly-amino acid of L-lysine, which is used as a safe food preservative. In this study, the effects of L-lysine and its isomer, D-lysine, on ε-PL biosynthesis and their metabolites by the ε-PL-producing strain Streptomyces ahygroscopicus GIM8 were determined. The results indicated that L-lysine added into the fermentation medium in the production phase mainly served as a precursor for ε-PL biosynthesis during the flask culture phase, leading to greater epsilon-PL production. At an optimum level of 3 mM L-lysine, a ε-PL yield of 1.16 g/L was attained, with a 41.4% increment relative to the control of 0.78 g/L. Regarding D-lysine, the production of ε-PL increased by increasing its concentrations up to 6 mM in the initial fermentation medium. Interestingly, ε-PL production (1.20 g/L) with the addition of 3 mM D-lysine into the initial fermentation medium in flasks was higher than that of the initial addition of 3 mM L-lysine (1.06 g/L). The mechanism by which D-lysine improves ε-PL biosynthesis involves its utilization that leads to greater biomass. After S. ahygroscopicus GIM8 was cultivated in the defined medium with L-lysine, several key metabolites, including 5-aminovalerate, pipecolate, and L-2-aminoadipate formed in the cells, whereas only L-2-aminoadipate was observed after D-lysine metabolism. This result indicates that L-lysine and D-lysine undergo different metabolic pathways in the cells. Undoubtedly, the results of this study are expected to aid the understanding of ε-PL biosynthesis and serve as reference for the formulation of an alternative approach to improve ε-PL productivity using L-lysine as an additional substrate in the fermentation medium.