Comparative proteomic analysis revealed the metabolic mechanism of excessive exopolysaccharide synthesis by Bacillus mucilaginosus under CaCO₃ addition

Abstract

The metabolic mechanism of excessive exopolysaccharide (BMPS) synthesis by Bacillus mucilaginosus CGMCC5766 under CaCO₃ addition was investigated. Under CaCO₃ (5 g/L), the maximum BMPS concentration reached 28.4 g/L, which was 11.2 folds higher than that of the control. Proteomics was then used to analyze the proteins with substantial differences expressed by B. mucilaginosus with and without CaCO₃ addition. The proteomic results revealed that the enzymes related to the central metabolic pathway, amino acid biosynthesis, and nucleotide metabolism were depressed. By contrast, the UDP–glucose pyrophosphorylase involved in BMPS biosynthesis was overexpressed and converted metabolic flux from the biomass accumulation to the biosynthesis of BMPS. This research provides a new and widened perspective into understanding the mechanism of BMPS biosynthesis and applying theoretical and practical significance for the improvement of BMPS production from B. mucilaginosus.

Keywords:

• Bacillus mucilaginosus
• CaCO₃
• exopolysaccharide
• proteomic

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China under Grant No. 31300026 and National first-classdiscipline program of Light Industry Technology and Engineering under Grant No. LITE2018-18.