Pretilachlor is one of the widely used chloroacetamide herbicides in Asian countries to control weeds in the rice field. The extensive use of herbicides has caused major concern among scientists throughout the world. Therefore, it is essential to develop an efficient method for the remediation of pretilachlor and its harmful by-products from contaminated surfaces. Mycoremediation is known to play a key role in the removal of various environmental contaminants. Hence, in the present study, strain AJN2 Aspergillus ficuum was isolated from a paddy field that was in continuous exposure to pretilachlor for over a decade. The degradation studies showed that the strain was efficiently able to degrade 73% of pretilachlor in an aqueous medium within 15 days of incubation and 70% of its major metabolite PME (2-methyl-6-ethylalanine). The GC/MS profile revealed the formation of aldehyde as the end product of degradation which was confirmed through the infrared fingerprint of the degradation sample. The ligninolytic enzyme activity studies showed that the lignin peroxidase enzyme system could be responsible for the degradation of pretilachlor and its major metabolite. The results highlight that the strain AJN2 A. ficuum could be a potential strain for the bioremediation of pretilachlor from the contaminated areas.
Keywords: 2-methyl-6-ethylalanine; Aspergillus ficuum; bioremediation; mycoremediation; pretilachlor.