title: Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria.
abstract: A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37 degrees C. It can utilize several (halo)aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30 degrees C with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no (chloro)catechol 2,3-dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China. qiyun2008@yahoo.com.cn
authors.forename: Yun
authors.initials: Y
authors.lastname: Qi
authors.forename: Lin
authors.initials: L
authors.lastname: Zhao
authors.forename: Ojekunle Z
authors.initials: OZ
authors.lastname: Olusheyi
authors.forename: Xin
authors.initials: X
authors.lastname: Tan
mesh_terms: D001673:Biodegradation, Environmental; D002723:Chlorobenzoates / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D049308:Dioxygenases / Q000378:metabolism; D012240:Rhodococcus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013696:Temperature
chemical_list: D002723:Chlorobenzoates; D004269:DNA, Bacterial; D012722:Sewage; D012989:Soil Pollutants; D049308:Dioxygenases