Biodehalogenation: The metabolism of vinyl chloride by Methylosinus trichosporium OB‐3b. A sequential oxidative and reductive pathway through chloroethylene oxide

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Abstract
Resting cell suspensions of the soil methylotroph Methylosinus trichosporium OB‐3b rapidly metabolize vinyl chloride The half‐life of the reaction, based on Cl release at pH 7 4, 0 1 in phosphate buffer with a cell density of 0 1 g/ml, is 0 61 h The path of metabolism is complicated but proceeds through the intermediacy of chloroethylene oxide Independent studies of the hydrolysis of this oxirane in water set its chemical half life at 3 9 min The products of its reaction with water are chloroacetaldehyde and hydroxyacetaldehyde They are produced in a ratio of 2 1, as judged by Cl release and 1H and 13C nuclear magnetic resonance analysis Incubations with vinyl chloride 1,2‐13C and vinyl chloride 1,2 14C establish that the dominant metabolic pathway entails a quick reduction of chloroethylene oxide to ethylene oxide Ethylene oxide is then converted in sequence to ethylene glycol, hydroxyacetaldehyde, glycolic acid, and CO2 This process is competitive with the chemical hydrolysis of chloroethylene oxide Similarly, chloroacetaldehyde is con verted to chloroacetic acid The latter is only slowly metabolized by this organism, and it accumulates throughout incubation to a final yield of 10% It is concluded that the organism participates in the hydrolysis of both chloroethylene oxide and ethylene oxide