Degradation of DDT and its analogs by Pseudomonas aeruginosa 640x.

Abstract

The possibility of complete degradation of DDT by Pseudomonas aeruginosa 640x was demonstrated in principle. A study of the conditions of degradation of DDT by this culture was made. It was demonstrated that only dechlorination of DDT to DDD is accomplished without addition of a supplementary substrate. The rest of the processes right up to the formation of benzhydrol and phenylacetic acid take place only under conditions of cometabolism. For dechlorination of the aliphatic fragment of DDT and the aromatic rings, anaerobic conditions, nitrates in the form of electron acceptors, and calcium lactate as a cosubstrate are preferred. Degradation of nonchlorinated benzophenone takes place only under aerobic conditions with glycerol as a cosubstrate. Phenylacetic acid and benzhydrol are used by the culture as sole sources of carbon; aerobic conditions are necessary for their degradation. On the basis of analysis of decomposition products of DDT and a study of the pathways of degradation of its metabolites and analogs, a means of converting DDT by P. aeruginosa 640x is proposed.