Characterization and Application of Biosurfactant producing Bacteria and Nanoparticle Synthesis for Bioremediation and Plant Growth Promotion

Biosurfactants are surface-active biomolecules with significant applications in bioremediation, particularly for the breakdown of hydrocarbon pollutants. This study investigates the isolation and characterization of biosurfactant-producing bacterial strains from oil-contaminated soils in Chennai, India, with a focus on Enterobacter cloacae. Screening assays including hemolysis, oil spreading and emulsification, identified Enterobacter cloacae as a promising candidate. Optimal production conditions: 37°C, pH 7, glucose and casein as carbon and nitrogen sources, yielded a high-performance biosurfactant. This biosurfactant facilitated the synthesis of silver nanoparticles (AgNPs), confirmed by UV-visible, FTIR, SEM and XRD analyses, demonstrating antimicrobial properties. Bioremediation potential was validated by applying the biosurfactant and its AgNP composite to oil-contaminated soils, showing significant hydrocarbon degradation. Additionally, Enterobacter cloacae exhibited plant growth-promoting traits such as nitrogen fixation and indole acetic acid production. These findings suggest that biosurfactants and biosurfactant-AgNP composites are effective agents for environmental remediation and sustainable agriculture.