Promoting cell growth for bio-chemicals production via boosting the synthesis of L/D-alanine and D-alanyl-D-alanine in Bacillus licheniformis

• Published in: World journal of microbiology & biotechnology Vol. 39; no. 5; p. 115
• Main Authors: Zhang, Zheng, He, Penghui, Hu, Shiying, Yu, Yanqing, Wang, Xiaoting, Ishaq, Ali Raza, Chen, Shouwen
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.05.2023; Springer Nature B.V
• Subjects: Acetic acid; Acetic Acid - metabolism; Acetoin; Alanine; ALD gene; Applied Microbiology; Bacillus licheniformis; Bacillus licheniformis - genetics; Bacillus licheniformis - metabolism; Biochemistry; Biomass; Biomedical and Life Sciences; Biotechnology; Butanediol; Cell growth; Cell proliferation; D-Alanine; D-Alanyl-D-alanine; Environmental Engineering/Biotechnology; Genes; Glutamic acid; L-Alanine; Lactic acid; Life Sciences; Metabolic Engineering; Metabolites; Microbiology; poly-γ-Glutamic acid; Polyglutamic Acid - metabolism; Synthesis; Metabolic engineering; Cell growth; Alanine and D-alanyl-D-alanine synthesis; Bio-chemicals; Bacillus licheniformis
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-023-03560-0

Metabolic engineering is a substantial approach for escalating the production of biochemical products. Cell biomass is lowered by system constraints and toxication carried on by the aggregation of metabolites that serve as inhibitors of product synthesis. In order to increase the production of biochemical products, it is important to trace the relationship between alanine metabolism and biomass. According to our investigation, the appropriate concentration of additional L/D-alanine (0.1 g/L) raised the cell biomass (OD 600 ) in Bacillus licheniformis in contrast to the control strain. Remarkably, it was also determined that high levels of intracellular L/D-alanine and D-alanyl-D-alanine were induced by the overexpression of the ald , dal , and ddl genes to accelerate cell proliferation. Our findings clearly revealed that 0.2 g/L of L-alanine and D-alanine substantially elevated the titer of poly-γ-glutamic acid (γ-PGA) by 14.89% and 6.19%, correspondingly. And the levels of γ-PGA titer were hastened by the overexpression of the ald , dal , and ddl genes by 19.72%, 15.91%, and 16.64%, respectively. Furthermore, overexpression of ald , dal , and ddl genes decreased the by-products (acetoin, 2,3-butanediol, acetic acid and lactic acid) formation by about 14.10%, 8.77%, and 8.84% for augmenting the γ-PGA production. Our results also demonstrated that overexpression of ald gene amplified the production of lichenysin, pulcherrimin and nattokinase by about 18.71%, 19.82% and 21.49%, respectively. This work delineated the importance of the L/D-alanine and D-alanyl-D-alanine synthesis to the cell growth and the high production of bio-products, and provided an effective strategy for producing bio-products.