Modulation of Acetyl-CoA Synthetase Expression Promoted Acetate Utilization and N-Acetylglucosamine Production in Bacillus subtilis

Abstract:

N-acetyl-D-glucosamine（GlcNAc） is an important functional monosaccharide. In the production of GlcNAc using recombinant Bacillus subtillis（B. subtilis）, accumulation of acetate inhibites cell growth and GlcNAc production, which also decreases GlcNAc yield. To construct a B. subtilis cell factory with efficient acetate utilization and GlcNAc production, expression of acetyl-CoA synthetase AcsA, which catalyzes the conversion of acetate to Ac-CoA, was modulated in this study. Specifically, the global transcriptional regulator CodY binding sites in the 5' UTR region of acsA were mutated to promote transcription of acsA；then, enzyme AcsA was modified by deacetylation to improve its activity. Finally, the accumulated acetate during shake flask fermentation reduced from 6.3 to 3.6 g/L, dry cell weight increased from 2.7 to 5.3 g/L, and the GlcNAc yield was increased by 163% up to 5.0 g/L, which indicated that the developed strain offers improved properties for GlcNAc production.