Modular pathway engineering of key precursor supply pathways for lacto-N-neotetraose production in Bacillus subtilis

Biotechnology for Biofuels

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[1] 0000 0001 0708 1323, grid.258151.a, Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China;0000 0001 0708 1323, grid.258151.a, Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China;0000 0001 0708 1323, grid.258151.a, Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, 214122, Wuxi, China;0000 0001 0708 1323, grid.258151.a, Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, 214122, Wuxi, China;0000 0001 0708 1323, grid.258151.a, Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China;State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co, Ltd, 200436, Shanghai, China;

关键词: N;    Bacillus subtilis;    Modular pathway engineering;    Human milk oligosaccharides;   

DOI  :  10.1186/s13068-019-1551-3

来源: publisher

【 摘 要 】

BackgroundLacto-N-neotetraose (LNnT) is one of the important ingredients of human milk oligosaccharides, which can enhance immunity, regulate intestinal bacteria and promote cell maturation.ResultsIn this study, the synthetic pathway of LNnT was constructed by co-expressing the lactose permease (LacY) β-1,3-N-acetylglucosaminyltransferase (LgtA) and β-1,4-galactostltransferase (LgtB) in Bacillus subtilis, resulting in an LNnT titer of 0.61 g/L. Then, by fine-tuning the expression level of LgtB, the growth inhibition was reduced and the LNnT titer was increased to 1.31 g/L. In addition, by modular pathway engineering, the positive-acting enzymes of the UDP-GlcNAc and UDP-Gal pathways were strengthened to balance the two key precursors supply, and the LNnT titer was improved to 1.95 g/L. Finally, the LNnT titer reached 4.52 g/L in a 3-L bioreactor with an optimal glucose and lactose feeding strategy.ConclusionsIn general, this study showed that the LNnT biosynthesis could be significantly increased by optimizing enzymes expression levels and modular pathway engineering for balancing the precursors supply in B. subtilis.

【 授权许可】

CC BY