Bioremediation of fipronil persistent pesticide by Pleurotus eryngii fungal biomass

Fipronil, a widely used phenylpyrazole pesticide, poses significant environmental and health risks due to its persistence and toxicity. Effective remediation strategies are urgently needed. In the present study, the biodegradation of fipronil pesticide was studied using Pleurotus eryngii, a white rot fungus, exploring its potential for environmental cleanup. The biomass was characterized by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques to verify the surface functionality and morphology. FTIR results revealed that fungal biomass is rich in multiple functional groups (OH, NH2, NH, C = O, CN etc.), while SEM analysis showed that the surface of fungal biomass is irregular, porous, rough, and heterogeneous in nature. Bioremediation of fipronil with P. eryngii was monitored using UV-visible spectroscopy. Box-Bhenken Design was applied to optimize various parameters such as pH, time, and concentration of substrate to obtain the maximum % biodegradation. It was found that using P. eryngii, 98% degradation of fipronil was achieved (0.228 mM) in 6 days at pH 6.5. Finally, gas chromatography–mass spectrometry analysis revealed that fipronil was transformed to benzaldehyde, (phenylmethylene) hydrazine and 1, 2- benzenedicarboxylic acid, mono (2-ethylhexyl) ester during degradation in presence of P. eryngii strain.