Biotransformation of 1,1,1-trichloroethane, trichloromethane, and tetrachloromethane by a Clostridium sp.
A gram-positive, strictly anaerobic, motile, endospore-forming rod, tentatively identified as a proteolytic Clostridium sp., was isolated from the effluent of an anaerobic suspended-growth bioreactor. The organism was able to biotransform 1,1,1-trichloroethane, trichloromethane, and tetrachloromethane. 1,1,1-Trichloroethane was completely transformed (greater than or equal to 99.5%) by reductive dehalogenation to 1,1-dichloroethane (30 to 40%) and, presumably by other mechanisms, to acetic acid (7%) and unidentified products. The reductive dehalogenation of tetrachloromethane led to the intermediate trichloromethane, which was further transformed to dichloromethane (8%) and unidentified products. The biotransformation occurred during the exponential growth phase, as well as during the stationary phase. Tetrachlorethene, trichloroethene, 1,1-dichloroethene, chloroethane, 1,1-dichloroethane, and dichloromethane were not biotransformed significantly by the organism.
Gälli
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Department of Civil Engineering, Stanford University, California 94305-4020.
McCarty
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PL
D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D002251:Carbon Tetrachloride / Q000378:metabolism*; D003013:Clostridium / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D008401:Gas Chromatography-Mass Spectrometry; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D014240:Trichloroethanes / Q000378:metabolism*
D003470:Culture Media; D006843:Hydrocarbons, Chlorinated; D014240:Trichloroethanes; C024566:1,1,1-trichloroethane; D002251:Carbon Tetrachloride