Treatment of an Endocrine Disruption Pesticide by Microbial Biodegradation Process

Abstract

Pesticides are widely used in agriculture to control a variety of pernicious organisms that spoil the crops. Nevertheless, low amounts of some residues may persist in the food supply, air, water and soil and could constitute a significant hazard pathway for humans. Most pesticides are classified by the World Health Organization as hazardous, and several widely used pesticides are known as potential Endocrine Disrupting Chemicals by the US Environmental Protection Agency (EPA). Bifenthrin insecticide, widely used in agriculture, constitutes a major environmental problem, because of its high toxicity and its persistence in the environment. It is now well established that Bifenthrin interferes with the action of female sex hormones, causing reductions in ovary weight and lack of oestrus and it decreases the level of thyroid hormones present in the blood. Bioremediation is a pollution control technology that uses biological systems to catalyze the degradation or transformation of various toxic chemicals. The present study involves the isolation of bacterial and fungal cultures metabolizing bifenthrin pesticide from soil having previously exposed to the pesticide. The biodegradation of bifenthrin insecticide was studied using these indigenous isolated fungi (Aspergillus niger and Rhizopus stolonifer) and bacteria (Aeromonas sp and Pseudomonas aeruginosa). The biodegradability was evaluated by the manometric respirometry test (OECD method 301F). The results showed that the evolution of biomass, biological oxygen demand (BOD) and chemical oxygen demand (COD) can highlight the biodegradation phenomenon. Maximum degrading potential was revealed by the fungi strains Aspergillus niger with 82.5% and Rhizopus stolonifer with 73.7% against 6 to11% for bacteria. The determined factorial design model successfully described the bifenthrin biodegradation phenomenon by the studied fungi. Therefore, the fungal strains might be useful for bioremediation of this endocrine disruption pesticide-contaminated environment. Keywords: Endocrine disruption pesticide / Bifenthrin / Microbial biodegradation.