Lindane biodegradation by the Fusarium verticillioides AT-100 strain, isolated from Agave tequilana leaves: Kinetic study and identification of metabolites

A fungal strain able to use lindane as a carbon and energy source under aerobic conditions was isolated from Agave tequilana leaves by enrichment techniques. With molecular techniques, it was identified as Fusarium verticillioides. The effect of a number of nutritional and environmental factors on the pesticide biodegradation was investigated using a Plackett-Burman design. Lindane biodegradation was higher in the presence of limited amounts of nitrogen and phosphorus. The addition of agave leaves to the culture medium and the use of higher concentrations of lindane, copper, and yeast extract improved the efficiency of the biodegradation process. The analysis of the metabolites using GC-MS identified gamma-penta-chlorocyclohexene and benzoic acid derivatives. This finding suggests that there is an aerobic carboxylation step, reported for the first time, in the lindane biodegradation pathway of F. verticillioides. Adding organic matter such as Agave tequilana leaves to the culture medium improved the fungal viability, eliminated the lag growth phase for fungal growth, and increased the pH value of the culture medium. The increased pH helped to overcome the toxicity of the benzoic acid derivatives that were released during lindane degradation. (C) 2012 Elsevier Ltd. All rights reserved.