Response surface methodology-based optimization of biosurfactant production from isolated Bacillus aryabhattai strain ZDY2

A potential biosurfactant producing isolate was identified as Bacillus aryabhattai strain ZDY2. Biosurfactant production was enhanced by 2.51-fold through the development of an optimized process using response surface methodology. The optimized culture medium contained crude oil 4.0%, yeast extract 0.7% and NaNO3 3.0% that yielded 8.86 g/l of biosurfactant. Biosurfactant was characterized for stability up to 100 °C, at pH 5–10 and in the presence of NaCl concentration up to 8%. Biosurfactant demonstrated antimicrobial activity against Salmonella typhimurium, Escherichia coli, Micrococcus luteus, Staphylococcus aureus and Candida tropicalis. The morphological characterization was carried out by scanning electron microscopy with energy-dispersive X-ray analysis. The Fourier-transform infrared spectroscopy analysis reveals the lipopeptide nature of the biosurfactant produced by B. aryabhattai strain ZDY2. The biosurfactant finds application in healthcare and pharmaceutical industries.