The ability of selected fungal strains to produce carboxylesterase enzymes for biodegradation and use of bifenthrin insecticide as carbon source: in vitro and in silico approaches.

ABSTRACT

Bifenthrin (BF) is a broad-spectrum type I pyrethroid insecticide that acts on insects by impairing the nervous system and inhibiting ATPase activity, and it has toxic effects on non-target organisms and high persistence in the environment. This study aimed to determine the potential of six different fungi, including Pseudozyma hubeiensis PA, Trichoderma reesei PF, Trichoderma koningiopsis PD, Purpureocillium lilacinum ACE3, Talaromyces pinophilus ACE4, and Aspergillus niger AJ-F3, to degrade BF. Three different concentrations of BF, including 0.1%, 0.2%, and 0.3% w/v, were used in the sensitivity testing that revealed a significant (p ≤ 0.01) impact of BF on fungal growth. Enzymatic assays demonstrated that both intracellular and extracellular carboxylesterases hydrolyzed BF with the enzymatic activity of up to 175 ± 3 U (µmol/min) and 45 ± 1 U, respectively. All tested fungi were capable of utilizing BF as a sole carbon source producing 0.06 ± 0.01 to 0.45 ± 0.01 mg dry biomass per mg BF. Moreover, the presence of PytH was determined in the fungi using bioinformatics tools and was found in A. niger, T. pinophilus, T. reesei, and P. lilacinum. 3D structures of the PytH homologs were predicted using AlphaFold2, and their intermolecular interactions with pyrethroids were determined using MOE. All the homologs interacted with different pyrethroids with a binding energy of lesser than - 10 kcal/mol. Based on the study, it was concluded that the investigated fungi have a greater potential for the biodegradation of BF.