DEGRADATION OF VARIOUS CHLOROPHENOLS UNDER ALKALINE CONDITIONS BY GRAM-NEGATIVE BACTERIA CLOSELY-RELATED TO OCHROBACTRUM-ANTHROPI

From concrete debris of a demolished herbicide production plant severa l Gram-negative bacterial strains were isolated, which exhibit metabol ic capabilities for the degradation of 2,4-dichlorophenol (DCP)(1)), 4 -chloro-2-methylphenol (MCP) and 4-chlorophenol (4-CP), while 2-chloro phenol (2-CP) was degraded at a slower rate. Degradative activity was inducible and was impeded by adding of 100 mg/l of chloramphenicol to growing cultures. The strains displayed alkaliphilic properties with o ptimum DCP/MCP degradation at pH values around 8.5-9.5; activity was o bserved up to pH values of 11. Degradation was most likely complete ac cording to chlorine balances; formation of intermediary products was o bserved with MCP some time. Specific activity of up to 380 mu mol/h . g dry mass was found within the concentration range of 10-20 mg/l DCP; higher concentrations retarded the activity with complete inhibition at 200-400 mg/l. Some of the strains carry plasmids whose presence was not unambiguously correlated to the degradative properties. Ribotypin g revealed a high degree of relationship between the strains. Prelimin ary taxonomic investigations showed close relationship to Ochrobactrum anthropi.