title: Isolation of biphenyl and polychlorinated biphenyl-degrading bacteria and their degradation pathway.
abstract: Four strains of biphenyl-degrading bacteria were isolated from a sewage and identified from the Rhodococcus genus (SK-1, SK-3, and SK-4) and Aquamicrobium genus (SK-2) by 16S rRNA sequence. Among these strains, strain SK-2 was most suitable for biphenyl degradation. When 0.65, 1.3, 2.6, or 3.9 mM of biphenyl was used, the biphenyl was completely degraded within 24 and 96 h of culture, respectively. However, in the case of 6.5 and 9.75 mM of biphenyl, the biphenyl degradation yields were about 80 % and 46.7 % after 120 h of culture, respectively. The isolated strains could degrade a broad spectrum of aromatic compounds including high-chlorinated polychlorinated biphenyl (PCB) congeners in the presence of biphenyl. In addition, strain SK-2 could utilize PCB congeners containing one to six chlorine substituents such as 2,2',4,4',5,5'-hexachlorobiphenyl. The PCB utilization rate by the strain SK-2 was increased compared to that of other PCB congener-utilizing bacteria. The four isolates metabolized 4-chlorobiphenyl to 4-chlorobenzoic acid and 2-hydroxy-6-oxo-6-(4'-chlorophenyl)-hexa-2,4-dienoic acid. These results suggest the isolated strains might be good candidates for the bioremediation of PCB-contaminated soil, especially high-saline soils.
authors.affiliation: Division of Applied Sciences, College of Environmental Technology, Graduate School of Engineering, Muroran Institute of Technology, 27-1 Mizumoto, Muroran, 050-8585, Hokkaido, Japan. ychang@mmm.muroran-it.ac.jp
authors.forename: Young-Cheol
authors.initials: YC
authors.lastname: Chang
authors.forename: Kazunori
authors.initials: K
authors.lastname: Takada
authors.forename: Dubok
authors.initials: D
authors.lastname: Choi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Toyama
authors.forename: Ken
authors.initials: K
authors.lastname: Sawada
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kikuchi
mesh_terms: D001673:Biodegradation, Environmental; D001713:Biphenyl Compounds / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D002723:Chlorobenzoates / Q000378:metabolism; D009566:Nitrates; D010802:Phylogeny; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D017680:Potassium Compounds; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012240:Rhodococcus / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D012965:Sodium Chloride; D013045:Species Specificity
chemical_list: D001713:Biphenyl Compounds; D002723:Chlorobenzoates; D009566:Nitrates; D017680:Potassium Compounds; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D012965:Sodium Chloride; D002244:Carbon; D011078:Polychlorinated Biphenyls; C040768:4-chlorobenzoic acid; C006983:4-chlorobiphenyl; C023844:potassium nitrate