Bacillus spp. of human origin: a potential siderophoregenic probiotic bacteria

Abstract

Bacillus spp. ST13, isolated from human stool, was evaluated for siderophoregenic and probiotic qualities prior to its possible application for iron nutrition in humans and animals. It was tested for siderophore production in iron-limiting conditions and found to produce catecholate type of siderophore on the basis of high-performance liquid chromatography (HPLC), FT-IR, NMR, and mass spectra analysis. The isolate was screened for probiotic properties as per WHO and FAO guidelines. The strain ST13 can survive stomach acidity, bile salt and partially simulated gastrointestinal tract conditions. It was susceptible to most of the antibiotic tested and showed antimicrobial activity against enteric pathogens like Salmonella typhimurium, Streptococcus pyogenes, and Staphylococcus aureus. Strain ST13 showed close similarity with Bacillus subtilis using 16S r-RNA gene sequence analysis and biochemical characterization. The methanolic extract of ST13 siderophore was evaluated for DPPH radical scavenging activity, which showed 94.55 ± 0.9% of radical scavenging effect.