Resting cell suspensions of the soil methylotroph Methylosinus trichosporium OB‐3b rapidly dehalogenate ethylene dichloride, but the process stops after one halogen is removed. Work with 14C‐ and 13C‐labeled 1,2‐dichloroethane shows that the biodehalogenation entails a direct hydrox‐ylation of one of the CCl bonds to produce chloroethanol. The latter is rapidly oxidized to chloroacetic acid. The organism does not metabolize this acid on the time scale of these experiments.

Resting cell suspensions of a soil Pseudomonus sp readily metabolize vinyl chloride Studies with a combination of I3C and I4C labeled vinyl chloride and metabolites establish that the initial dehalogenation step formally entails a direct hydroxylation of the C-C1 bond to produce acetaldehyde This substance undergoes biochemical oxidation at both the carbonyl and the methyl carbons to produce acetic acid and hydroxyacetaldehyde These are both further oxidized by the organism to hydroxyacetic acid (glycolic acid), and the latter is converted to carbon dioxide The rate of C1 liberation from vinyl chloride is a function of growth conditions Cells grown on 3 chloropropanol carry out the dehalogenation of vinyl chloride with a t,,, of 1 3 h at a cell density of 0 1 g/ml

Resting cell suspensions of a soil Pseudomonas sp readily metabolize vinyl chloride Studies with a combination of 13C and 14C labeled vinyl chloride and metabolites establish that the initial dehalogenation step formally entails a direct hydroxylation of the CCl bond to produce acetaldehyde This substance undergoes biochemical oxidation at both the carbonyl and the methyl carbons to produce acetic acid and hydroxyacetaldehyde These are both further oxidized by the organism to hydroxyacetic acid (glycolic acid), and the latter is converted to carbon dioxide The rate of Cl liberation from vinyl chloride is a function of growth conditions Cells grown on 3 chloropropanol carry out the dehalogenation of vinyl chloride with a t1/2 of 1 3 h at a cell density of 0 1 g/ml

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

Resting cell suspensions of the soil methylotroph Methylosinus trichosporium OB‐3b rapidly dehalogenate ethylene dichloride, but the process stops after one halogen is removed. Work with 14C‐ and 13C‐labeled 1,2‐dichloroethane shows that the biodehalogenation entails a direct hydrox‐ylation of one of the CCl bonds to produce chloroethanol. The latter is rapidly oxidized to chloroacetic acid. The organism does not metabolize this acid on the time scale of these experiments.