Effect of chlorobenzoates on the degradation of polychlorinated biphenyls (PCB) by Pseudomonas stutzeri

Chlorobenzoic acids (CBA) are frequently dead-end products of partial aerobic biodegradation of polychlorinated biphenyls (PCB). When CBA produced from PCB accumulate in the growth medium, they can inhibit the bacterial growth and consequently, slow down PCB biodegradation. In this study, the effects of seven mono- and dichlorinated CBA on growth of Pseudomonas stutzeri on different substrates and on the PCB degradation by this strain in a liquid mineral medium were tested. 3-CBA was the strongest growth inhibitor for P. stutzeri growing on glucose, benzoate and biphenyl. It was found to inhibit heavily the elimination of some di- and trichlorinated biphenyls. In contrast, its influence on the elimination of more chlorinated congeners was much less significant.The authors are with the Department of Biochemical Technology, Faculty of Chemical Technology, Slovak Technical University, 812 37 Bratislava, Slovakia.