Earthworm gut microbiota: A novel biocatalyst for the sustainable degradation of carbendazim in Agro-ecosystems

Carbendazim is a widely used fungicide in agriculture, poses significant environmental risks due to its persistence in terrestrial and aquatic ecosystems. To investigate the potential for bioremediation of carbendazim, three bacterial strains, Bacillus aureus PPH1, Bacillus paralicheniformis PPH2, and Bacillus stercoris PPH3, were isolated from the gastrointestinal tract of Glyphidrilus sp. earthworms, a common inhabitant of paddy fields. In a controlled laboratory experiment, all the strains were incubated with 100 mg/L carbendazim in minimal salt medium for five days. The HPLC analysis revealed that B. aureus PPH1, B. paralicheniformis PPH2, and B. stercoris PPH3 degraded 87.18%, 89.66%, and 91.21% of carbendazim, respectively. LC-MS/MS analysis subsequently confirmed the existence of 2-aminobenzimidazole and 2-hydroxybenzimidazole as major metabolites, suggesting a potential biotransformation pathway for carbendazim degradation. This investigation offers novel insights into the biodegradation mechanisms of carbendazim facilitated by gut bacteria of paddy field earthworms.