Untargeted metabolomics-based investigation of amino acid effects on antimicrobial peptides production in Paenibacillus ehimensis HD 8-3 fermentation

Abstract

Antimicrobial peptides (AMPs), as new antimicrobial products, have wide application prospects in food, medicine, and other fields. A strain of Paenibacillus ehimensis HD was previously identified by our research group, and the AMPs synthesized by this strain were found to be highly stable and had a broad antimicrobial spectrum. To enhance the AMPs yield, the ultraviolet-atmospheric and room temperature plasma mutagenesis (UV-ARTP) was adopted in P. ehimensis HD in this study. A stable mutant of P. ehimensis HD 8-3, with enhanced AMPs production, was obtained. Subsequently, using the resting cell culture system and untargeted metabolomics analysis, we found that the addition of L-lysine (Lys) or L-asparagine (Asn) was beneficial to the growth of P. ehimensis HD 8-3, while Asn also enhanced the AMPs production. The metabolites associated with the carbohydrate, glycolytic pathway, TCA cycle, pentose phosphate pathway (PPP), and amino acid metabolism were upregulated under the addition of two amino acids during the rapid growth phase of P. ehimensis HD 8-3, providing precursors and energy for the strain growth or AMPs production. These results indicate that the appropriate addition of exogenous Lys and Asn is an effective strategy to increase AMPs yield in P. ehimensis HD 8-3.