Metabolomic unravelling and RSM-assisted optimization of phenylpyrazole degradation by a novel soil-derived bacterial...

The empirical bioremediation propensity of phenylpyrazole insecticide-degrading bacteria is restrained by their low efficiency and low environmental resilience. In this study, we synthesized a novel microbial consortium, FP-25, comprising two indigenous strains-Pseudomonas sp. strain S4 and Agrobacterium sp. strain S6-isolated from perpetually contaminated agricultural soil and capable of degrading the phenylpyrazole insecticide fipronil. Optimization of biodegradation variables such as neutral pH (7.0), temperature (32.5 °C), an inoculum concentration of 0.175 g L⁻¹, and 200 mg L⁻¹ of fipronil concentration, through response surface methodology (RSM), resulted in degradation efficiency of 91.92% within 14 days of incubation in aqueous media. The generation of degradation products was confirmed through GC-MS analysis. Consequently, a catabolic pathway for fipronil degradation used by the consortium FP-25 has been elucidated, depicting the successive enzymatic transformations of fipronil into non-toxic metabolites. The adequacy and validity of the RSM model were evaluated through an in-situ microcosm experiment using contaminated soil sampled from the Himalayan highland ecosystem. Degradation kinetics substantiated first-order reaction models with rate constants ranging between 0.046 and 0.076 day⁻¹. Thus, the present study demonstrated the potent bioremediation ability of the developed consortium FP-25 as an eco-friendly and sustainable substitute for conventional approaches.

The online version contains supplementary material available at https://doi.org/10.1007/s13205-026-05081-7.