Enhancement of poly-γ-glutamic acid production by alkaline pH stress treatment in Bacillus licheniformis WX-02

2015 ◽  
Vol 91 (9) ◽  
pp. 2399-2403 ◽  
Author(s):  
Jia Wang ◽  
Honglun Yuan ◽  
Xuetuan Wei ◽  
Jiangang Chen ◽  
Shouwen Chen
Keyword(s):  
Glutamic Acid ◽  
Bacillus Licheniformis ◽  
Acid Production ◽  
Alkaline Ph ◽  
Stress Treatment ◽  
Ph Stress ◽  
Glutamic Acid Production ◽  
Alkaline Ph Stress

scholarly journals Promoting Cell Growth And Poly-Y-Glutamic Acid Production By Boosting The Synthesis of Alanine And D-Alanyl-D-Alanine In Bacillus Licheniformis

2022 ◽  
Author(s):  
Zheng Zhang ◽  
Penghui He ◽  
Shiying Hu ◽  
Yanqing Yu ◽  
Xiaoting Wang ◽  
...  
Keyword(s):  
Cell Growth ◽  
Microbial Biomass ◽  
Glutamic Acid ◽  
Bacillus Licheniformis ◽  
Alanine Racemase ◽  
High Yield ◽  
Effective Strategy ◽  
Genes Encoding ◽  
Alanine Synthesis ◽  
Glutamic Acid Production

Abstract Objective: The production of some bio-chemicals affected by the cell growth. This study aimed at promoting the cell growth by overexpressing the synthesis of peptidoglycans tetrapeptide tail components to improve poly-γ-glutamic acid (γ-PGA) production. Results: L-alanine, D-alanine and D-alanyl-D-alanine are primary precursors for the synthesis of peptidoglycans. The addition of L-alanine and D-alanine significantly increased both the cell growth and production of γ-PGA. Then, several genes encoding key enzymes for L/D-alanine and D-alanyl-D-alanine biosynthesis were overexpressed respectively, including ald (encoding alanine dehydrogenase), dal (encoding alanine racemase) and ddl (encoding D-alanine ligase). The results showed that the overexpression of genes ald , dal and ddl increased the production of γ-PGA by 19.72%, 15.91% and 60.90%, and increased the microbial biomass by 15.58%, 18.34% and 49.85%, respectively. Moreover, we demonstrated that the overexpression of genes ald , dal and ddl increased γ-PGA production mainly by enhancing cell growth rather than providing more precursors. Conclusions: This work illustrated the importance of the L/D-alanine and D-alanyl-D-alanine synthesis to the cell growth and the high yield of γ-PGA, and provided an effective strategy for producing γ-PGA .

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