2-chlorobiphenyl and diphenyl

The biphenyl-degrading strain, Pseudomonas sp. KM-04, was isolated from polychlorinated biphenyls-contaminated soil sample obtained from the vicinity of a former coal mine. We herein report that strain KM-04 can use biphenyl as a sole carbon source, and resting cells convert biphenyl to its corresponding metabolic intermediates. Incubation of KM-04 with autoclaved mining-contaminated soil for 10 days in a slurry system reduced the levels of biphenyl and 2-chlorobiphenyl by 98.5 % and 82.3 %, respectively. Furthermore, treatment of a mine-soil microcosm with strain KM-04 for 15 days in a composting system under laboratory conditions reduced the levels of biphenyl and 2-chlorobiphenyl by 87.1 % and 68.7 %, respectively. These results suggest that KM-04 is a potential candidate for the biological removal of biphenyl and its chlorinated derivatives from polychlorinated biphenyl-contaminated mining areas.

Topics: Biodegradation, Environmental; Biphenyl Compounds; Coal; Mining; Pseudomonas; Soil; Soil Microbiology; Soil Pollutants

Metabolism of simple aromatic compounds in rhizobial strains has been a subject of study for a few decades, due either to the significance of nutritional diversity in the inoculum survival during agricultural applications or to the importance of plant phenolics in the microbe-plant cross-talk and signal-transduction. Here, we report the capability of rhizobial strains to catabolize polychlorinated biphenyls (PCBs). In order to identify the genes in these strains that mediate the catabolism of PCBs we used the bphABC genes from Comamonas testosteroni strain B-356. Our results showed that genomic DNAs from all four rhizobial strains studied hybridized strongly with the Comamonas-derived probe, indicating the presence of a similar genetic system. This is a novel and interesting finding indicating for the first time, perhaps, of a role of rhizobia in recycling of aromatic compounds in nature and, certainly, opening a new avenue to be explored in the field of bioremediation.

Topics: Aroclors; Biotransformation; Biphenyl Compounds; Environmental Pollutants; Genes, Bacterial; Gram-Negative Aerobic Bacteria; Polychlorinated Biphenyls; Sequence Homology, Nucleic Acid; Sinorhizobium meliloti; Species Specificity

1. A comparison was made between rat hepatic and plant microsomal cytochrome P-450 and cytochrome P-450 linked enzymic activities. 2. The results show that, compared with plant microsomes, rat hepatic microsomal protein concentrations were 165-fold higher, and rat hepatic cytochrome P-450 concentration were 32-fold higher. 3. Rat hepatic Cytochrome P-450 linked enzyme activities were 1765-fold and 25-fold greater when compared with plant microsomes using aldrin and biphenyl as substrates, respectively. 4. Rats metabolised biphenyl to 2- and 4-hydroxybiphenyl, whereas plants produced only the latter metabolite. 5. Pretreatment of rats and plant tissues with biphenyl, Aroclor 1248 and the sodium salt of phenobarbital increased significantly the microsomal protein concentrations, and enzyme activities linked to cytochrome P-450. 6. Unlike rat microsomes, those of plants were unable to metabolise halosubstituted biphenyls at measurable rates.

Topics: Aldrin; Animals; Aroclors; Biphenyl Compounds; Cytochrome P-450 Enzyme System; Epoxy Compounds; Female; Fungicides, Industrial; Hydroxylation; Microsomes; Microsomes, Liver; Phenobarbital; Plants; Rats; Spectrophotometry, Infrared; Xenobiotics