Bacterial dehalogenation of chlorobenzoates and coculture biodegradation of 4,4'-dichlorobiphenyl.
Acinetobacter sp. strain 4CB1 was isolated from a polychlorobiphenyl-contaminated soil sample by using 4-chlorobenzoate as a sole source of carbon and energy. Resting cells of Acinetobacter sp. strain 4CB1 hydrolytically dehalogenated 4-chlorobenzoate under aerobic and anaerobic conditions, but 4-hydroxybenzoate accumulated only under anaerobic conditions. Cell extracts of Acinetobacter sp. strain 4CB1 oxidized 4-hydroxybenzoate by an NADH-dependent monooxygenase to form protocatechuate, which was subsequently oxidized by both ortho- and meta-protocatechuate dioxygenase reactions. When grown on biphenyl, Acinetobacter sp. strain P6 cometabolized 4,4'-dichlorobiphenyl primarily to 4-chlorobenzoate; however, when this strain was grown in a coculture with Acinetobacter sp. strain 4CB1, 4-chlorobenzoate did not accumulate but was converted to inorganic chloride. When resting cells of Acinetobacter sp. strain 4CB1 were incubated anaerobically with 3,4-dichlorobenzoate, they accumulated 4-carboxy-1,2-benzoquinone as a final product. Since 3,4-dichlorobenzoate is a product that is formed from the cometabolism of 3,4-dichloro-substituted tetrachlorobiphenyls by Acinetobacter sp. strain P6, the coculture has a potential application for dehalogenation and mineralization of specific polychlorobiphenyl congeners.
Adriaens
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Department of Soil and Environmental Sciences, University of California, Riverside 92521.
Kohler
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Kohler-Staub
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Focht
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D000150:Acinetobacter / Q000201:enzymology / Q000378:metabolism*; D000332:Aerobiosis; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D055598:Chemical Phenomena; D002621:Chemistry; D002723:Chlorobenzoates / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D012988:Soil Microbiology; D013379:Substrate Specificity
D002723:Chlorobenzoates; D011078:Polychlorinated Biphenyls; C029861:4,4'-dichlorobiphenyl; D010105:Oxygenases