MICROBIAL UTILIZATION OF THE HYDROCARBON COMPONENTS OF ATRAZINE IN A TROPICAL SOIL ENVIRONMENT SOUTHWEST, NIGERIA.

Abstract

Biodegradation of atrazine, a xenobiotic-substance recently introduced into agricultural practice in Nigeria was assessed using native soil microorganisms. Field experiment and laboratory studies confirmed that bacterial and fungal consortium utilize the hydrocarbon component of atrazine and thereby mineralize the somewhat recalcitrant organic chemical. The atrazine-degraders were isolated on Minimal salt medium and sabouraud dextrose agar supplemented with atrazine at 0.05g/L and incubated at 28 ±2oC for 72 hrs and 5 days respectively. The sampled agricultural soil was of alkaline pH while the optimum pH at which the microbial consortium metabolize atrazine was acidic (mean pH 5.63). Total viable count of bacterial atrazine-degraders were 602.5 x 105cfu/ml. Bacterial atrazine-degraders were: Micrococcus sp., Bacillus sp. Enterobacter Sp and Pseudomonas sp. While fungal atrazine-degraders were: Aspergillus fumigatus, A. niger, Penincillium sp and Fusarium sp.