Lindane biodegradation by the Fusarium verticillioides AT-100 strain, isolated from Agave tequilana leaves: Kinetic study and identification of metabolites Flor de Ma. Guillén-Jiménez a , Eliseo Cristiani-Urbina b , Juan C. Cancino-Díaz c , Jorge L. Flores-Moreno d , Blanca E. Barragán-Huerta a, * a Departamento de Ingeniería en Sistemas Ambientales, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu s/n, Unidad Profesional Adolfo López Mateos, CP 07738, México, D.F., Mexico b Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala s/n, Col. Santo Tomás, CP 11340, México, D.F., Mexico c Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala s/n, Col. SantoTomás, CP 11340, México, D.F., Mexico d Universidad Autónoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, CP 02200, México, D.F., Mexico article info Article history: Received 21 July 2011 Received in revised form 2 April 2012 Accepted 7 April 2012 Available online 9 August 2012 Keywords: Lindane Agave tequilana Fusarium verticillioides Aerobic carboxylation abstract 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 PlacketteBurman 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 effi- ciency of the biodegradation process. The analysis of the metabolites using GCeMS identified g-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. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Technical lindane is a mixture of several isomers of hexa- chlorocyclohexane (HCH) that is produced industrially by the photochemical chlorination of benzene under a UV light (Okeke et al., 2002). As the g-isomer of HCH, commonly known as lindane or g-HCH, is the only one of these isomers that exhibits effective insecticidal properties (Quintero et al., 2005), it has been used extensively for agricultural applications and in the public health service. Because of its high toxicity, persistence, mobility in the envi- ronment, and bioaccumulation in the food chain, the production and use of lindane is prohibited or severely restricted in many countries (Barriada-Pereira et al., 2005; Mertens et al., 2005). Nevertheless, the problem of lindane residues still exists in these countries, possibly due to the widespread distribution of this isomer, which is caused, in part, by its continued use in some developing countries for economic reasons. Another potential source of lindane pollution is the large unused stockpiles of pure and/or technical lindane in many areas (Okeke et al., 2002). Many studies have described the adverse effects of lindane, which primarily affects the central nervous system and appears to cause renal and hepatic toxicity (U.S. EPA, 2006). In mammals, acute lindane intoxication may cause respiratory dysfunction, generalized trembling, hyper-salivation, and convulsions, which can lead to death in extreme cases (Pesce et al., 2008). It has been shown that lindane may be an endocrine disrupting chemical (EDC); this is evidenced by the fact that it induces reproductive impairment, including adverse effects on the male and female reproductive system, gestation, and fetal development (Traina et al., 2003). * Corresponding author. Tel.: þ52 55 57296300x52310; fax: þ52 55 57296300x52300. E-mail addresses: bbarraganh@ipn.mx, bbarraga59@yahoo.com (B.E. Barragán- Huerta). Contents lists available at SciVerse ScienceDirect International Biodeterioration & Biodegradation journal homepage: www.elsevier.com/locate/ibiod 0964-8305/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ibiod.2012.04.020 International Biodeterioration & Biodegradation 74 (2012) 36e47