Biodegradation of polychlorinated biphenyls in Aroclor 1232 and production of metabolites from 2,4,4'-trichlorobiphenyl at low temperature by psychrotolerant Hydrogenophaga sp. strain IA3-A.
OBJECTIVE
To determine the extent and pattern of degradation of polychlorinated biphenyls (PCBs) in Aroclor 1232 at 5 degrees C by a psychrotolerant bacterium, and to confirm the formation of intermediates of PCB metabolism at low temperature using 2,4,4'-trichlorobiphenyl (2,4,4'-TCB).


RESULTS
10 ppm of Aroclor 1232 or 100 micromol l(-1) 2,4,4'-TCB was incubated with biphenyl-grown cells at 5 degrees C or 30 degrees C for 48 or 72 h. Degradation of PCBs and the products of metabolism of 2,4,4'-TCB were confirmed by gas chromatography and mass spectrometry. Extents of degradation of many of the PCBs were similar at 5 degrees C and 30 degrees C. The extent of biodegradation of PCBs in Aroclor 1232 at 5 degrees C was dependent on chlorination pattern. The 14 chlorine-containing intermediates of 2,4,4'-TCB metabolism, which were detected, include several isomers of dihydrodiols, dihydroxy compounds and meta-cleavage compounds.


CONCLUSIONS
The bacterium will be useful for bioremediation of PCB-contaminated sites in cold climates; however, knowledge of the products of PCB metabolism is necessary, as they could be more toxic than the parent compounds.


CONCLUSIONS
Substantial degradation of some PCBs in Aroclor 1232 was demonstrated at low temperature within 48 h. The detection of several isomeric intermediates suggests that multiple pathways are used to transform PCBs in this strain. For the first time, formation of metabolic products from 2,4,4'-TCB at low temperature is confirmed.
Lambo
A J
AJ
Department of Biology, Applied Microbiology and Biotechnology Laboratory, Memorial University of Newfoundland, St John's, NF, Canada. adewalelambo2@hotmail.com
Patel
T R
TR
D001140:Aroclors / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003080:Cold Temperature; D042621:Comamonadaceae / Q000302:isolation & purification / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D053858:Metabolic Networks and Pathways; D008956:Models, Chemical; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D012988:Soil Microbiology
D001140:Aroclors; C081766:2,4,4'-trichlorobiphenyl; D011078:Polychlorinated Biphenyls