Anti-biofilm and disinfectant-like activity of pumilacidin, a lipopeptide biosurfactant produced by Bacillus pumilus NITDID1

Biosurfactants are unique secondary metabolites produced by several microorganisms that have the potential to be used as antimicrobial agents in the pharmaceutical and food sectors. The present study explored the antibacterial and anti-biofilm potential of pumilacidin isolated from Bacillus pumilus NITDID1. In vitro, this lipopeptide biosurfactant inhibited all pathogens used in this study. The membrane disruption of tested bacteria was confirmed by intracellular nucleic acid and protein content release assay. Additionally, the membrane disruption of the biosurfactant-treated bacterial cell was visually confirmed by fluorescence microscopy. The effect of various parameters on the antimicrobial activity of pumilacidin was investigated, and it was found that they could withstand a wide range of temperatures and were resistant to proteolytic enzymes. The biosurfactant exhibited significant anti-adherence activity at 10 mg/ml concentrations against all the tested bacteria on a pre-treated polystyrene surface. A maximum antiadherence effect was observed against Pseudomonas aeruginosa MTCC1688, with a percentage inhibition of 93.90%. Pumilacidin also could successfully prevent the initial deposition of microbes that form biofilms on silicone surfaces and significantly decrease biofilm formation. The findings of this study addressed the antibacterial and anti-biofilm properties of this biosurfactant and open possibilities for its usage as a surface coating agent in industrial pipelines and machinery.