CHARACTERIZATION OF A DEGRADATIVE PLASMID CODING FOR METABOLISM OF 3-CHLOROBENZOATE BY PSEUDOMONAS-PUTIDA AND ITS EXPRESSION IN ESCHERICHIA-COLI

Pseudomonas putida DP4 was isolated from an enrichment culture with 3- chlorobenzoate (3-Cba) as sole source of carbon and energy. This strai n was adapted to grow on 3-Cba at higher concentrations and maximum gr owth was observed at 12.8 mM of 3-Cba with 0.5 mM glucose as co-substr ate. Further increase in the concentration of 3-Cba resulted in lower growth and degradation efficiency. The degradation of 3-Cba was not co mplete, since accumulation of the corresponding chlorocatechol resulte d in inhibition of metabolism. The genes coding for the metabolism of 3-Cba were found to be plasmid-borne. The purified plasmid was transfo rmed to rec(-) Escherichia coli DH5 at a rate of 2.28 X 10(4). The tra nsformed cells were able to grow on 3.2 mM of 3-Cba and showed the pre sence of a corresponding plasmid DNA profile.