Genomic evaluation of BC4, a consortium of four Alkalihalobacillus clausii isolates, confirms its probiotic potential and safety in usage

Four strains of Alkalihalobacillus clausii B603/Nb (resistant to rifampicin), B619/R (resistant to streptomycin), B637/Nm (resistant to tetracyclin) and B106 (resistant to chloramphenicol) were isolated from various sources and used to prepare a consortium designated as BC4. Genomes of the constituent strains of the BC4 consortium were evaluated to investigate their genetic makeup and determine their probiotic potential. Gene prediction and functional annotation were performed using RAST. The data obtained was mined for genes encoding various phenotypic traits. This analysis revealed the presence of several genes encoding probiotic attributes like (i) survivability in the presence of low pH, bile, oxidative stress; (ii) bacterial aggregation and adhesion to gut epithelium, etc.; and (iii) enzymes/ molecules conferring health benefits. Further, the genome analysis also confirmed the genes required for enhancing the nutritional amenability, health-promoting, and disease-preventing traits were present. Several genes encoding multiple antibiotic resistance were detected; however, none of these genes was located on mobile elements such as plasmids, transposons, etc. The absence of genes encoding virulence factors, pathogenic islands, emetic toxins, etc., as well as mobile genetic elements, underscored the safety of BC4 isolates.