Sustainable Disruption of Microbial Biofilms: Functional and Antimicrobial Assessment of a Lipopeptide Biosurfactant.

Biofilm-associated infections pose significant challenges due to the increased antibiotic resistance of microorganisms within these structures. This study involved isolating and characterizing the biosurfactant produced by Bacillus subtilis RSL-2 using molasses to develop a sustainable antibiofilm agent. The biosurfactant was identified as a surfactin-like lipopeptide (molecular weight: 1037 g/mol) based on FTIR, 1H NMR, and HRMS analyses. It demonstrated a low critical micelle concentration (CMC) of 70 mg/L and markedly decreased surface and interfacial tensions to 24.46 and 0.46 mN/m, respectively. Functional experiments revealed significant surface activity, as evidenced by a 2.2 cm oil-displacement zone and an emulsification index of 91% in toluene. The surfactin demonstrated concentration-dependent antibacterial and antibiofilm efficacy against Staphylococcus aureus, Enterococcus hirae, Bacillus subtilis, Escherichia coli, Agrobacterium, Pseudomonas aeruginosa, Aspergillus, and Candida at their respective IC90 values. The producer strains exhibited high IC90 values, likely reflecting their inherent tolerance to surfactants. Surfactin's eco-friendliness, antibiofilm activity, and functional adaptability make it a promising agent for managing biofilms in both medicinal and industrial applications. This work highlights the strategic potential of molasses-derived biosurfactants as environmentally friendly and sustainable options for antibacterial and antifungal applications, particularly for addressing biofilm-associated infections.