Screening of Bacillus spp. of Human Origin A Potential Siderophorgenic Probiotic Bacteria

Abstract

Siderophorgenic Bacillus strain FM 22 and FM 23 has been isolated from faecal sample of 8- month-old healthy infant. It was evaluated for probiotic characters (WHO guidelines) and siderophore production for iron nutrition in human and animals to make iron more soluble biologically. Partial 16S-rRNA sequencing analysis showed that isolates exhibited homology with Bacillus subtilis. Isolates FM 22 and FM 23 were found to produce maximum siderophore ranging from 65-90 % at an optimum pH 7, incubation period of 72 h, agitation speed of 150 rpm and inoculum volume of 15 %. The above two isolates produced hydroxymate type of siderophores under iron stressed conditions. Strains have shown excellent tolerance to acid, bile salt, sodium chloride and phenol, non-haemolytic in nature and exhibited high hydrophobicity and autoaggregation Further, isolates showed antimicrobial activity against enteric pathogen like Staphylococcus aureus, E. coli and Klebsiella pneumoniae and exhibited moderate susceptibility to antibiotics tested.