Reductive dechlorination of 2,4-dichlorobenzoate to 4-chlorobenzoate and hydrolytic dehalogenation of 4-chloro-, 4-bromo-, and 4-iodobenzoate by Alcaligenes denitrificans NTB-1.
Alcaligenes denitrificans NTB-1, previously isolated on 4-chlorobenzoate, also utilized 4-bromo-, 4-iodo-, and 2,4-dichlorobenzoate but not 4-fluorobenzoate as a sole carbon and energy source. During growth, stoichiometric amounts of halide were released. Experiments with whole cells and cell extracts revealed that 4-bromo- and 4-iodobenzoate were metabolized like 4-chlorobenzoate, involving an initial hydrolytic dehalogenation yielding 4-hydroxybenzoate, which in turn was hydroxylated to 3,4-dihydroxybenzoate. The initial step in the metabolism of 2,4-dichlorobenzoate was catalyzed by a novel type of reaction for aerobic organisms, involving inducible reductive dechlorination to 4-chlorobenzoate. Under conditions of low and controlled oxygen concentrations, A. denitrificans NTB-1 converted all 4-halobenzoates and 2,4-dichlorobenzoate almost quantitatively to 4-hydroxybenzoate.
D000421:Alcaligenes / Q000254:growth & development / Q000378:metabolism*; D001970:Bromobenzoates / Q000378:metabolism*; D002723:Chlorobenzoates / Q000378:metabolism*; D006868:Hydrolysis; D007463:Iodobenzoates / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology
D001970:Bromobenzoates; D002723:Chlorobenzoates; D007463:Iodobenzoates; C040768:4-chlorobenzoic acid; D010100:Oxygen