关键词: 联苯菊酯；谢瓦氏曲霉；生物降解；降解特性

Abstract: Bifenthrin (BF), a pyrethroid insecticide widely used in tea plantation, can persist in the environment, posing potential risks to tea safety, ecological balance, and human health. In this study, a fungal strain capable of efficiently degrading BF, designated G11, was obtained from the “Golden Flower” in Fu brick tea and identified as Aspergillus chevalieri based on morphological characteristics and ITS sequence analysis. Degradation kinetics experiments revealed that under optimal conditions of 30 ℃ and pH 6.0, strain G11 degraded (66.32 ± 4.66)% of 10 mg/L BF within 192 h. Although the biomass accumulation, ((6.21 ± 0.46) g/L), was inhibited by the substrates, the strain still exhibited strong tolerance. Moreover, strain G11 demonstrated broad-spectrum degradation potential against other pyrethroids (PYRs), degrading (60.80 ± 4.17)% of cypermethrin, (54.90 ± 1.65)% of fenvalerate, and (32.66 ± 3.38)% of deltamethrin at 20 mg/L within 192 h. From the degradation products of BF, the ester hydrolysis product 2-methyl-3-phenylbenzyl alcohol was identified by gas chromatography-mass spectrometry (GC-MS). Using 2-methyl-3-phenylbenzyl alcohol and trifluoro-chlorothric acid as model substrates, the metabolic capacity of strain G11 for these intermediates was verified, with degradation rates of (26.18 ± 1.13)% and (12.91 ± 0.94)%, respectively. In a simulated Fu brick tea fermentation system, strain G11 degraded (20.05 ± 1.03)% of BF within 240 h. These findings provide a safe microbial strain resource and a theoretical basis for the control of PYRs residues in fermented tea and the elucidation of their degradation mechanisms.

Key words: bifenthrin; Aspergillus chevalieri; biodegradation; degradation characteristics