Identification and characterization of a putative novel bacteriocin from Bacillus velezensis G02 and its effects on the intestinal microflora in mice.

Bacteriocins are defined as proteins that are produced by bacteria and that have antibacterial effects on various pathogenic bacteria. This study explored the effects of the crude extract of bacteriocin produced by Bacillus velezensis G02 (PRJNA1303554) on the intestinal microbiota of normal mice. Observation through liver and kidney tissue sections showed that the bacteriocin crude extract had no obvious adverse reactions on the internal organs of mice, and no mice died. A 16 S rDNA amplicon sequencing analysis revealed that the crude extract of the bacteriocin significantly changed the α-diversity (Shannon (P = 0.51), Simpson (P = 0.51), and Chao1 (P = 0.28)) and β-diversity (PCoA, (P = 0.1) NMDS, (P = 0.0132)) of the intestinal microbiota in normal mice, reducing the species abundance and increasing the evenness of their intestinal microbiota. In addition, the bacteriocin PG02 crude extract exhibited broad-spectrum antibacterial activity against both gram-positive and gram-negative bacteria. The purified bacteriocin was identified by LC-MS/MS in combination with sequence coverage analysis; its molecular weight was found to be 20.1 ~ 31 kDa, and it was speculated to be a putative novel bacteriocin named bacteriocin PG02. This study provides a reference for the microbiology field research and development of feed additive.