Characterization of bacillus isolates using whole genome sequencing analysis and application as a potential food probiotic

Abstract

Whole-genome sequencing (WGS) performed to evaluate potential probiotic properties of Bacillus species (6-2, 63-11 & 78-1) pre-reflecting antimicrobial properties, identified them as Bacillus velezensis (98.16%), Bacillus infantis (91.21%) and Bacillus amyloliquefaciens (99.06%) respectively. It also predicted K-mer resistance to cfr(B) and tet(L) proteins (6-2 & 78-1); bacteriocin and metabolite synthesis (6-2 & 78-1), terpenoid gene (63-11); hemolysin III (6-2 & 78-1) and hlyIII homolog (63-11); extracellular protease (6-2 & 63-11) and cell-bound protease (78-1) genes. WGS gut adaption F1F0 ATP, chaperonin (groEL, groES) and general stress response proteins (DnaK); EAL domain protein (biofilm), flagellin synthesis, and putative integral membrane proteins (63-11 & 78-1) were also annotated. The in-vitro assessment demonstrated a significant effect on growth and performance under gastric (78-1) and bile acid conditions (63-11) along with high hydrophobicity to chloroform (6-2) and xylene (63-11 & 78-1). It also reflected moderate (6-2 & 78-1) to high (63-11) susceptibility towards Ampicillin, Chloramphenicol and Tetracycline, and moderate (63-11) to high (6-2 & 78-1) antagonistic effects towards pathogens, with no hemolytic activity (except 78-1). Based on the findings of both the tests, this study provides enough evidence to support the potential benefits and commercial applications of Bacillus species, with B. infantis (63-11) being the most potential probiotic candidate.