Production of Biosurfactants from Halophilic Bacteria Isolated from Hydrocarbon-contaminated Soils and Their Application in Soil Recovery

Abstract

This study investigated the potential of biosurfactant-producing halophilic bacteria isolated from hydrocarbon-contaminated soils and evaluated their application in soil recovery. Soil samples collected from contaminated sites and an uncontaminated control were analyzed for physicochemical properties, microbial population density, and plant growth response following biosurfactant treatment. The results shows that contaminated soils exhibited acidic to near-neutral pH (5.6–6.2), reduced organic matter content (1.9–2.3%), elevated electrical conductivity (3.6–4.1 dS/m), and high total petroleum hydrocarbon concentrations compared with the control soil. Halophilic bacterial populations ranged from 5.6 × 10⁵ to 6.8 × 10⁵ CFU/g in contaminated soils and were significantly higher than the control (p < 0.05). Biosurfactant-producing isolates were presumptively identified as Bacillus, Pseudomonas, and Halomonas species. Application of biosurfactants significantly improved plant growth compared with untreated soils, with isolate-specific differences observed. Statistical analysis using one-way ANOVA revealed significant differences (p < 0.05) between treated and control soils for key measured parameters. The findings demonstrate that biosurfactant-producing halophilic bacteria can enhance hydrocarbon-impacted soil recovery and support their potential application in environmentally sustainable remediation strategies.