Degradation of 4-Chlorobenzoic Acid by a Pseudomonas sp.

A bacterium capable of utilizing 4-chlorobenzoic acid as its sole carbon source was isolated from soil and tentatively identified as a species of Pseudomonas. The organism is also able to grow on the 4-chloro- and 4-bromo-derivatives of benzoate, phenylacetate, and phenylalanine.

During growth on 4-chlorobenzoic acid, 4-hydroxybenzoate and protocatechuate were accumulated in the culture medium. Protocatechuate was broken down by ortho-fission and further metabolized via the β-ketoadipate pathway. In extracts of 4-chlorobenzoategrown cells, the enzymes responsible for the degradation of 4-chlorobenzoic acid were detected. 4-Chlorobenzoic acid proved to be the only inducer of the dehalogenating enzyme, of 4-hydroxybenzoate 3-hydroxylase and of protocatechuate 3,4-dioxygenase.