Characteristics of a novel probiotic of Bacillus velezensis isolated in Xinjiang

Abstract Bacillus velezensis (B. velezensis) is a new generation of probiotics that has excellent benefits, bacteriostatic activity, and growth-promoting activity. In this study, a novel B. velezensis strain, B. velezensis XJC-1, was isolated from healthy cats in Xinjiang. This strain exhibited a certain tolerance to acidic conditions (pH 3.0 for 6 h), bile salts (0.1% and 0.3% for 6 h), and high temperatures (50°C, 60°C and 70°C for 10 min). Whole-genome sequencing (WGS) revealed that XJC-1 (GenBank Accession: JBPEKN000000000) yielded a total of 36 scaffolds, encompassing 3,916,364 base pairs (bp) in total, with an average G+C content of 46.31%. UniProtKB/Swiss-Prot annotates stress resistance genes, such as dnaK , which aligns with the observed phenotypic traits. AntiSMASH-7.1.0 identified 20 secondary metabolite clusters, especially six 100% similar biosynthesis-related gene clusters (bacillaene, bacilysin, bacinapeptin, bacillibactin, bacillothiazols A-N and macrolactin H), which are correlated with the inhibitory effects against Escherichia coli , Staphylococcus aureus and Salmonella enteritidis . In the safety evaluation, XJC-1 was sensitive to 8 antibiotics, and in silico polymerase chain reaction (PCR) screening revealed that there were no common enterotoxin-related genes in the genome of XJC-1. In addition, there were no acquired drug resistance genes or common food-borne bacterial virulence genes in its genome. Critically, gas chromatography–mass spectrometry (GC–MS) analysis revealed that XJC-1 produced short-chain fatty acids (SCFAs), with acetic acid being the major component (418 mg/L), which was consistent with the metabolism of cofactors/vitamins pathway in the Kyoto Encyclopedia of Genes and Genomes (KEGG) as well as 46 glycoside hydrolase (GH) and 40 glycosyl transferase (GT) genes annotated in the Carbohydrate-Active enZYmes (CAZy) database. These findings highlight XJC-1’s potential as a feline probiotic.