Utilization and cooxidation of chlorinated phenols by Pseudomonas sp. B 13

Abstract

Pseudomonas sp. B13 was grown in continuous culture on 4-chlorophenol as the only carbon source. Maximum growth rate of 0.4 h(-1) was observed at a substrate concentration of greater than 0.01 mM and less than 0.15 mM. In addition to the enzymes of phenol catabolism, high specific 1,2-dioxygenase activities with chlorocatechols as substrates were found. The isomeric monochlorinated phenols were also totally degraded by 4-chlorophenol grown cells. (+)-2,5-Dihydro-4-methyl- and (+)-2,5-dihydro-2-methyl-5-oxo-furan-2-acetic acid were formed in high yield as dead-end catabolites from cooxidation of cresoles. Several dichlorophenols except 2,6-dichlorophenol were removed from the culture fluid by chlorophenol grown cells. Ring cleavage of chlorinated catechols were shown to be one of the critical steps in chlorophenol catabolism. A catabolic pathway for isomeric chlorophenols is discussed.