Exploring the Potential of Lipopeptide Biosurfactants Produced by Lysinibacillus sp. for Oil Removal and Polycyclic Aromatic Hydrocarbon Degradation in Soils.

Crude oil is a complex mixture containing aliphatic and polyaromatic hydrocarbons (PAHs), along with other toxic constituents. Environmental contamination from oil spills, biomass burning, pyrogenic coal combustion, and industrial discharges leads to elevated PAH concentrations in soil, which can inhibit natural degradation processes and leads to cancer in human beings. Being a green approach, biosurfactants are promising strategies for enhancing oil removal, PAHs degradation due to it’s surface tension reducing property. In this study, a biosurfactant (BS) was isolated from Lysinibacillus sp. MW444883 and identified as a lipopeptide using FTIR, GC-FID, LC-HRMS, and 1H NMR spectroscopy. The BS effectively reduced the viscosity of 50% crude oil at 25, 35, and 45 °C, and remained stable across a wide pH range, salt concentrations and temperatures. Oil dispersion, assessed through RGB image analysis, ranged from 56.4% to 86.6%. An HPLC system was optimized to quantify key PAHs: naphthalene, fluorene, phenanthrene, and pyrene. Three biosurfactant-based formulations-bead (PB), water-dispersible granule (PWDG), and soluble liquid (PSL) were tested in both acidic and alkaline Inceptisol soils. Compared to control soils, the PAH half-lives decreased significantly (up to 7-fold) under treatment. Among the formulations, PSL was most effective. CO₂ release ranged from 189 to 430 mg kg⁻¹ d⁻¹ in alkaline and 146–401 mg kg⁻¹ d⁻¹ in acidic soils, indicating enhanced microbial activity and degradation efficiency.