Toxicological Assessment and Biodegradability of a Microbial Glycolipid Biosurfactant for Environmental Applications

The environmental application of microbial biosurfactants requires a thorough and systematic evaluation of their ecological safety to ensure their suitability for sustainable use. In this study, we investigated the toxicity profile and environmental compatibility of a glycolipid biosurfactant produced by a novel Pseudomonas fluorescens strain isolated from Tunisian soil. A series of ecotoxicological assays were conducted to assess its impact on different components of the ecosystem. Phytotoxicity tests performed on Lepidium sativum seeds revealed no inhibitory effects on seed germination, root elongation, or overall plant growth, demonstrating excellent compatibility with terrestrial plants and suggesting its safe application in soil environments. Acute toxicity is currently being evaluated using the Microtox® assay with Vibrio fischeri to determine EC50 values and further characterize its ecological safety.

In addition, biodegradability assays demonstrated that the biosurfactant is readily biodegradable, with more than 60% degradation achieved within four days under standard conditions. Stability studies indicated that the biosurfactant remains structurally and functionally stable across a wide range of temperatures (30–80 °C) and pH values (2–10), without generating toxic degradation by-products. 

Compared to conventional synthetic surfactants, the studied biosurfactant exhibited a significantly lower ecological risk profile, combining low toxicity, rapid biodegradability, and high functional stability. These findings support its potential as a safe, sustainable, and environmentally compatible alternative for large-scale bioremediation applications.