Degradation of Fenclorim and Other Pesticides in Soil and Water by Isolated Microorganisms

Fenclorim is an effective safener that protects rice (Oryza sativa L.) from the phytotoxic effects of certain herbicides. This study investigated its impact on soil bacterial communities, isolated fenclorim-degrading bacteria, assessed environmental contamination by fenclorim and other pesticides, and enhanced their degradation in soil and water under aerobic conditions. Results showed that fenclorim did not adversely affect bacterial community structure. Acinetobacter sp. F0, capable of using fenclorim as a sole carbon, nitrogen, and energy source, was isolated from soil and degraded 97.1 ± 1.2% of fenclorim (100 µM) within 36 hours. Fenclorim was more persistent in soil and water than pretilachlor, butachlor, and pymetrozine. Co-inoculation with target-degrading microorganisms significantly enhanced the degradation of all compounds and reduced the accumulation of intermediate metabolites—4,6-dichloropyrimidine and benzene—via cross-degradation. A packed-bed bioreactor achieved degradation efficiencies of 93.7 ± 4.59% for fenclorim, 94.9 ± 4.09% for pretilachlor, and 90.4 ± 5.52% for butachlor at a 12-hour hydraulic retention time. The reactor also effectively removed BOD₅, COD, NO₃⁻, NH₄⁺, and PO₄³⁻ from water. These findings provide valuable insights into fenclorim degradation pathways, pesticide persistence, and the role of microbial augmentation in environmental remediation.