Chlordane Biodegradation Under Aerobic Conditions By Actinobacteria Strains

BOURGUIGNON, NATALIA; CUOZZO, SERGIO A.; FUENTES, MARÍA S.; BENIMELI, CLAUDIA S.; AMOROSO, MARÍA J.

Actinobacteria: Application in Bioremediation and Production of Industrial Enzymes.

Science Publishers

Lugar: New Hampshire; Año: 2013; p. 227 - 240

Persistent organic pollutants (POPs) are organic compounds that remain intact in the environment for long periods, favoring their wide geographical distribution. They accumulate in the fatty tissue of living organisms and their toxic effect on humans and wildlife has been proven (Hirano et al. 2007). Chlordane (C10H6Cl8, 1,2,4,5,6,7,8,8a-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-methanoindene) is an organochlorine pesticide that has been used worldwide, especially during the early 1980s, on farmlands, lawns in houses and gardens and also as a termiticide for foundations in houses (Dearth and Hites 1990, Colt et al. 2009).Commercially available technical-grade chlordane (CLD) is a mixture of over 140 different but related compounds; the three most common components among them are α -(cis-) chlordane,  γ -(trans-) chlordane and trans-nonachlor (Dearth and Hites 1990).Many of the chlordane components and their metabolites are ubiquitous and persistent and have a tendency for biomagnifi cation. They have been shown to be toxic in higher animals; they are suspected to be carcinogenic and may have estrogenic activities (Chia et al. 2010, Liu et al. 2010). Technical chlordane, along with many other organochlorine pesticides, has been phased out from the market under the UNEP (United Nations Environmental Program) and has been included in the group of persistent organic pollutants (UNEP 2000). Although chlordane ranks among the “dirty dozen” priority pollutants established during the Stockholm Convention, a global treaty to protect human health and the environment that came into force in May 2004 (Wong et al. 2005), this pesticide is still detected in food and environmental samples around the world (Barber et al. 2006, Hageman et al. 2006, Yago et al. 2006, Bempah and Donkor 2010, Jia et al. 2010, Lal et al. 2010). There is great concern about the adverse effects on the ecosystem. It is not only important to monitor sites where chlordane was used and where pesticide stockpiles were managed but it is also crucial to assess the risk of chlordane remaining in the environment.To date, little fundamental research on chlordane biodegradation has been carried out and there are only very few studies on the degradation pathways or degradation products of this compound (Yamada et al. 2008). Actinobacteria have a great potential for biodegradation of organic and inorganic toxic compounds (Ravel et al. 1998). There exist studies demonstrating how these microorganisms have been able to oxidize and partially dechlorinate and dealkylate organochlorine pesticides such as aldrin, DDT, metolachlor and atrazine (Liu et al. 1990, 1991, Radosevich et al. 1995). In our laboratory, Benimeli et al. (2003, 2006, 2007) and Fuentes et al. (2010, 2011) isolated and selected wild actinobacteria strains, which were tolerant to lindane and able to remove it from culture media and soil. Cuozzo et al. (2009) detected dechlorinase activity and lindane catabolism products as a result of microbial lindane degradation by  Streptomyces sp. M7, isolated in Tucumán, Argentina. However, to our knowledge, there exists only one report about an actinobacterium strain ( Nocardiopsis sp.) isolated from soil that has been able to metabolize pure cis- and trans-chlordane in a pure culture (Beeman and Matsumura 1981). The aim of this work was to evaluate whether indigenous actinobacteria strains isolated from contaminated environments in Argentina would be able to remove and degrade technical-grade chlordane from culture medium and soil samples under aerobic conditions.