Atrazine degradation by wild filamentous fungi

Abstract

Bioremediation is a promising technology for the treatment of polluted areas due to its minor cost;moreover, indigenous fungi had not been already applied to detoxify contaminated habitats. The kinetic of atrazine degradation by Gliocladium roseum, Mucor alternans and Pycnidiophora dispersa were assessed in soluble and soil sorbed herbicide with different organic matter content. Their half-saturation constants, Km, expressed the affinity for the substrate, being 12.5, 3.8 and 2.7 μg/ml for G. roseum, M. alternans and P. dispersa. Moreover, Vmax, uptake rate/ biomass, assumed by the asymptotes of each fungal curves were 43.5-41.0, 37.5-35.0 and 26.5-24.5 μg Atz/min-1. mg for G. roseum, M. alternans and P. dispersa, respectivelly. The 65-75% was in soluble phase, that was preferentially degraded by fungi. Our results showed that the atrazine transformation were consistent with those in pure cultures, suggesting that the parameters derived from in-vitro studies may be useful to predict the herbicide detoxification in polluted sediments. Fungal kinetic allowed us to predict the atrazine degradation in natural contaminated habitats and was in relation to the herbicide levels especially in soil solutions.