Metabolic Conversion of Lindane to Chlorophenols, Hydrophobic Acids, and More Hydrophilic Products by Streptomyces PSI
Several streptomycetes known to metabolize organochlorides or lignocellulose were tested for their ability to break the recalcitrant carbon-chlorine bond using the insecticide lindane (hexachlorocyclohexane) as a model substrate. Streptomyces PSI rapidly converted [U-14C] lindane to a mixture of water-soluble metabolites when grown on tryptone-yeast extract at 28°C for one to five days. Chemical analysis of the products showed extensive aromatization with formation of a trichlorophenol, as well as extensive conversion to water-soluble acids, other more hydrophilic products, and CO2. Several pigment-negative mutants were isolated which still converted lindane to the same metabolites, but the wild-type organism would not grow on lindane as its sole carbon source. With higher concentrations of lindane (0.1 mg/ml), both the wild-type and a pig-mutant strain converted 20% to water solubility in six days.