Degradation of Hexachlorocyclohexanes and Structurally Related Substances by Clostridium Sphenoides

Washed cell suspensions of C. sphelloides adapted to the y-isomer of 1,2,3,4,5,6-hexachlorocyclohexane (y-HCH), metabolized IX- and y-HCH but not p- and o-HCH. Temperature and pH optima for the metabolism of y- HCH were found to be 40°C and pH 8 ·0. The y-HCH-adapted suspensions also metabolized the P-, y- and o-isomers of 3,4,5,6-tetrachloro-l-cyclohexene, 2,3,4,5,6-pentachloro-2- cyclohexen-l-ol, y-l ,2,3,4,5,6-pentachlorocyclohex-l-ene, and 1,2,3,4,5-pentachlorocyclohexane. The suspensions did not metabolize a selection of chlorinated benzenes, dichlorocyclohexane and chlorocyclohexane.