Efficient production of ε-poly-l-lysine from glucose by two-stage fermentation using pH shock strategy. (December 2017)

• Record Type: Journal Article
• Authors: Pan, Long; Chen, Xu-Sheng; Liu, Ming-Ming; Liu, Yong-Juan; Mao, Zhong-Gui
• Is Part Of: Process biochemistry. Volume 63(2017)
• Page Start: 8
• Page End: 15
• Publication Date: 2017-12
• Subjects: Two-stage fermentation -- ε-poly-l-lysine -- pH shock -- Streptomyces albulus -- Acid tolerance; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2017.08.008
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: A novel two-stage fermentation based on the conventional pH shock fermentation was developed. ε-PL production and productivity reached 32.22 g/L and 5.86 g/L/day, respectively, with the novel two-stage fermentation. PH shock strategy enhanced ε-PL production, which might be related to the acid tolerance of S. albulus . The results would be useful for large-scale ε-PL production. Abstract: In this study, a pH shock strategy was employed to enhance ε-poly-l -lysine (ε-PL) production from glucose. In the conventional fermentation, in the early stage, only 13% of total ε-PL production is achieved in 25% of the entire fermentation period, which severely affected ε-PL productivity. To improve the efficiency of ε-PL production during fermentation, a novel two-stage fermentation, namely culture and fermentation stages, was proposed on the basis of the analysis of conventional pH shock fermentation. After optimization of parameters such as inoculum growth conditions, initial fermentation pH, and inoculum volume, the ε-PL production and productivity achieved using the novel fermentation process in a 5-L fermenter reached 32.22 g/L and 5.86 g/L/day, which were 32.3% and 36.6% higher, respectively, when compared with those obtained in conventional fermentation. Furthermore, evaluation of acid tolerance of mycelia collected from the pH shock fermentation showed that pH shock enhanced ε-PL production, which might be related to the acid tolerance of Streptomyces albulus and pH stress (pH 3.0). The results obtained could be useful for large-scale ε-PL production and to provide new information on ε-PL biosynthesis mechanism.