Dechlorination of 4-chlorobenzoate by Pseudomonas sp. DJ-12

4-Chlorobiphenyl-degrading Pseudomonas sp. DJ-12 was able to degrade 4-chlorobenzoate (4CBA), 4-iodobenzoate, and 4-bromobenzoate completely under aerobic conditions. During the degradation of 4CBA by Pseudomonas sp. DJ-12, chloride ions were released by dechlorination and 4-hydroxybenzoate was produced as an intermediate metabolite. The NotI-DNA fragments of pKC157 containing dechlorination genes hybridized with the gene encoding 4CBA : CoA dehalogenase of Pseudomonas sp. CBS3 which is responsible for the hydrolytic dechlorination of 4CBA. These results imply that Pseudomonas sp. DJ-12 degrades 4CBA to 4-hydroxybenzoate via dechlorination as the initial step of its degradative pathway. The genes responsible for dechlorination of 4CBA were found to be located on the chromosomal DNA of Pseudomonas sp. DJ-12.