Evaluation of biosurfactant production from Pseudomonas mendocina and its antibacterial application

This study highlights the production and characterization of biosurfactants from Pseudomonas mendocina 7094 using low-cost substrates, an approach aimed at reducing costs and promoting sustainability. Under selected conditions, the biosurfactant yield reached 4.85 ± 0.16 g/L, outperforming yields reported for other Pseudomonas species. The biosurfactant exhibited exceptional stability across extreme pH (2-12), temperature (20–120 °C), and salinity (0–12 %) ranges, highlighting its potential for industrial applications. It effectively reduced surface tension to 28.42 ± 0.3 mN/m and achieved high emulsification indices (68.4 %–72.9 %) under diverse environmental conditions. Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the biosurfactant as dirhamnolipids, consistent with previously reported findings. The antibacterial potential was assessed against six human pathogens, with significant inhibition observed, particularly against Bacillus cereus 8733 (Zone of Inhibition: 19 ± 0.1 mm; Minimum Inhibitory Concentration: 32 μg/ml). The biosurfactant exhibited notable anti-adhesive and anti-biofilm activities, achieving biofilm eradication rates between 56.39 % and 77.25 %. Its strong antibacterial activity against both Gram-positive and Gram-negative pathogens, coupled with antibiofilm and anti-adhesive properties, positions it as a promising natural antimicrobial agent for biomedicine and food safety. These findings establish P. mendocina 7094 biosurfactants as sustainable, cost-effective alternatives to synthetic surfactants, with versatile applications across diverse industries.