Isolation and identification of a potent probiotic Bacillus paramycoides strain SCS_MS2 from cheese whey-microbial fuel cell.

Due to the increasing prevalence of antibiotic-resistant pathogens, probiotics as alternatives to antibiotics are receiving growing attention from scientists and healthcare providers as a strategy to reduce the emergence of antibiotic-resistant microbes. Accordingly, this work is carried out for the isolation of a potent probiotic from a non-conventional source, cheese whey-microbial fuel cell. A bacterial strain SCS_MS2 isolated from bioanode of the cheese whey-microbial fuel cell was a Gram-positive bacterium having more than 98% 16S rRNA gene sequence similarity with Bacillus paramycoides. Therefore, the isolate was named Bacillus paramycoides strain SCS_MS2. Strain SCS_MS2 exhibited remarkable inhibitory activity against Shigella boydii, Escherichia coli, Shigella dysenteriae, and Staphylococcus aureus. The strain was able to grow at pH 2, with a survival rate of 77%, and tolerated salt concentrations of up to 6.5% NaCl. Additionally, strain SCS_MS2 showed good cell surface hydrophobicity and auto-aggregation capability, enhancing its potential for biofilm formation. The strain also showed notable antioxidant activity with low cytotoxicity. These findings indicate that Bacillus paramycoides strain SCS_MS2 has strong probiotic potential and may be applicable for improving human health as well as for use in poultry and cattle farming.