Simultaneous biosurfactant production and bioremediation of polycyclic aromatic hydrocarbons and diesel fuel by a novel Pseudomonas fluorescens from Tunisian soil

Biosurfactant-producing bacteria offer a sustainable solution for the remediation of persistent environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs). Here, we report a novel Pseudomonas fluorescens strain isolated from Tunisian soil, capable of degrading high-molecular-weight PAHs including phenanthrene, pyrene, and anthracene. The strain produced biosurfactants that lowered surface tension from 71.2 to 37.6 mN/ m, with a critical micelle concentration (CMC) of 60.92 mg/L, enhancing PAH solubility and bioavailability. Characterization confirmed its glycolipid nature, high emulsification (E24 > 90 %), stability across 30–80 ◦C and pH 2–10, rapid biodegradability (>60 % in 4 days), and exhibited no phytotoxic effects in the assays. Moreover, it outperformed several synthetic surfactants in hydrocarbon remobilization. These results highlight the strain’s potential as a highly effective and eco-friendly agent for PAH bioremediation in contaminated environments.