title: Cometabolic degradation of dibenzofuran and dibenzothiophene by a newly isolated carbazole-degrading Sphingomonas sp. strain.
abstract: A carbazole-utilizing bacterium was isolated by enrichment from petroleum-contaminated soil. The isolate, designated Sphingomonas sp. strain XLDN2-5, could utilize carbazole (CA) as the sole source of carbon, nitrogen, and energy. Washed cells of strain XLDN2-5 were shown to be capable of degrading dibenzofuran (DBF) and dibenzothiophene (DBT). Examination of metabolites suggested that XLDN2-5 degraded DBF to 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienic acid and subsequently to salicylic acid through the angular dioxygenation pathway. In contrast to DBF, strain XLDN2-5 could transform DBT through the ring cleavage and sulfoxidation pathways. Sphingomonas sp. strain XLDN2-5 could cometabolically degrade DBF and DBT in the growing system using CA as a substrate. After 40 h of incubation, 90% of DBT was transformed, and CA and DBF were completely removed. These results suggested that strain XLDN2-5 might be useful in the bioremediation of environments contaminated by these compounds.
authors.affiliation: State Key Laboratory of Microbial Technology, College of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Gai
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Cuiqing
authors.initials: C
authors.lastname: Ma
authors.forename: Jinhui
authors.initials: J
authors.lastname: Feng
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.forename: Ping
authors.initials: P
authors.lastname: Xu
mesh_terms: D001483:Base Sequence; D001572:Benzofurans / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002227:Carbazoles / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004785:Environmental Pollutants / Q000378:metabolism*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013056:Spectrophotometry, Ultraviolet; D020578:Sphingomonas / Q000235:genetics / Q000378:metabolism*; D013876:Thiophenes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001572:Benzofurans; D002227:Carbazoles; D004785:Environmental Pollutants; D012336:RNA, Ribosomal, 16S; D013876:Thiophenes; C041514:carbazole; C023614:dibenzofuran; C016366:dibenzothiophene