Actinobacteria as bio-tools for removing and degrading α-, β- and γ-hexachlorocyclohexane

Abstract

The organochlorine insecticide γ-hexachlorocyclohexane (γ-HCH), also called lindane, and its non-insecticidal isomers α- and β- continue generating serious environmental and health concerns, although their use has been restricted or completely banned. Therefore, the removal of pesticides from the environment, or their transformation into less toxic compounds is a topic of research interest worldwide. This chapter discusses the potential of actinobacteria, mainly those belonging to the Streptomyces genus, to remove the isomers of hexachlorocyclohexane under different physicochemical conditions. Furthermore, the optimal pH and temperature conditions for the removal of hexachlorocyclohexane by regional Streptomyces strain (Streptomyces sp. M7) are presented. This chapter also reports the ability of this actinobacterium to remove a mixture composed of α-, β- and γ-HCH (lindane), which is important considering that multiple isomers are normally present in contaminated sites. This chapter highlights the ability of actinobacteria to remove α-, β-, and γ-HCH isomers from liquid and soil systems, under a diverse set of physicochemical conditions and postulates actinobacteria as potential agents to bioremediate environments contaminated with organochlorine pesticides.