Degradation of 3-chlorobenzoate in Soil by Pseudomonads Carrying Biodegradative Plasmids

Degradation of continuously added 3-chlorobenzoate (3-CB) was studied in samples of chernozem soil. Soil columns were inoculated with Pseudomonas putida growing on 3-CB and carrying the biodegradation plasmid and with Pseudomonas aeruginosa incapable of growth on 3-CB and carrying the inserted biodegradation plasmid pBS 2 determining ortho-cleavage of the aromatic ring. While the 3-CB degradation was observed in both inoculated variants, the native microflora of the soil under study was incapable to degrade 3-CB. Among pseudomonads isolated from inoculated soil at different stages of cultivation and growth on 3-CB, some had the taxonomic features of P. putida as well as those differing in 1-5 characteristics. The study of the activities of the enzymes cleaving the aromatic ring revealed the presence of pyrocatechol 1,2-dioxygenase in the isolated strains only, as estimated by means of benzoate and 3-CB as substrates.