小白链霉菌全细胞转化L-赖氨酸合成ε-聚赖氨酸的体系构建与优化  

Construction and optimization of whole-cell transformation method for ε-poly-L-lysine production from L-lysine by Streptomyces albulus

作　　者：朱道君 刁文娇 张佳微 王靓[1,2] 张宏建 张建华[1,2] 陈旭升 ZHU Daojun;DIAO Wenjiao;ZHANG Jiawei;WANG Liang;ZHANG Hongjian;ZHANG Jianhua;CHEN Xusheng(School of Biotechnology,Jiangnan University,Wuxi 214122,China;The Key Laboratory of Industrial Biotechnology,Ministry of Education,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学生物工程学院,江苏无锡214122 [2]工业生物技术教育部重点实验室(江南大学),江苏无锡214122

出　　处：《食品与发酵工业》2024年第1期29-36,共8页Food and Fermentation Industries

基　　金：国家自然科学基金面上项目(31671846);江苏省重点研发计划项目(BE2022703)。

摘　　要：小白链霉菌(Streptomyces albulus)是天然抗菌肽ε-聚赖氨酸(ε-poly-L-lysine,ε-PL)的主要生产菌株。为了提高小白链霉菌生产ε-PL效率,该文构建并优化了全细胞转化L-赖氨酸合成ε-PL体系:葡萄糖质量浓度80 g/L,菌龄12 h,反应温度30℃,L-赖氨酸质量浓度15 g/L,柠檬酸浓度15 g/L,初始反应p H 4.0,硫酸铵质量浓度6 g/L,湿菌体量为1900 g/L。基于该转化体系,实现小白链霉菌在96 h合成ε-PL产量和底物转化率达到13.80 g/L和38.9%,分别是常规摇瓶发酵的4.1、3.2倍。最后,在小白链霉菌中异源表达来自大肠杆菌的L-赖氨酸特异性通透蛋白基因lysp,获得的重组菌S.albulus OE-lysp实现L-赖氨酸利用能力和底物转化率较出发菌株分别提升26%和33%,ε-PL产量增加至17.21 g/L,约为常规摇瓶发酵ε-PL产量的6.4倍,这是文献报道的最高摇瓶规模ε-PL产量。该研究结果一方面说明了通过全细胞转化L-赖氨酸生产ε-PL的可行性,另一方面为S.albulus转化大宗氨基酸L-赖氨酸生产高值ε-PL奠定了坚实的技术基础,具有重要的理论意义和经济价值。Streptomyces albulus is the main producer of ε-poly-L-lysine(ε-PL).ε-PL is a natural antimicrobial peptide used primarily as a biological preservative in food industry,but its widespread application is limited by its high costs.To improve the production efficiency of S.albulus,this study used a whole-cell transformation method to produce ε-PL.Firstly,the synthesis efficiency of ε-PL in different fermentation systems was compared,and the whole-cell transformation system was found to produce the highest ε-PL yield,reaching 10.74 g/L.Then,the transformation medium and conditions were systematically optimized,and the optimal transformation conditions was obtained:glucose 80 g/L,cell culture time 12 h,reaction temperature 30℃,L-lysine 15 g/L,citric acid 15 g/L,initial pH 4.0,(NH 4)2SO 46 g/L,and wet biomass 1900 g/L.In the optimal system,the ε-PL yield and substrate conversion rate reached 13.80 g/L and 38.9%,respectively,which were 4.1 and 3.2 folds higher than those in shake flask fermentation system.Finally,the L-lysine specific permease gene(lysp)from Escherichia coli BL21 was heterologous expressed to enhance the strain’s ability to uptake exogenous L-lysine.Compared with the starting strain,the recombinant strain S.albulus OE-lysp showed a 26% increase in L-lysine utilization rate and a 33% increase in substrate conversion rate.The ε-PL yield also increased by 17.21 g/L,about 6.4 times higher than that in shake flask fermentation system,which is to our knowledge the highest reported ε-PL production in shake flask fermentation system.The results demonstrate the feasibility of producing ε-PL using a whole-cell transformation method and provide a solid technical foundation for the production of high-value ε-PL using L-lysine.Therefore,this study has important theoretical significance and high economic value.

关 键 词：小白链霉菌 Ε-聚赖氨酸 全细胞转化 异源表达 L-赖氨酸通透蛋白 

分 类 号：TS201.3[轻工技术与工程—食品科学]