Phylogenetic and phenotypic diversity of 4-chlorobenzoate-degrading bacteria isolated from soils

Twenty numerically dominant 4-chlorobenzoate (4-CBA)-degrading bacteria wer e isolated from agricultural soils. The isolates were able to utilize 4-CBA as a sole source of carbon and energy. A total of 65% of the isolates was identified to the species level by fatty acid methyl ester (FAME) analysis, and the isolates were strains of Micrococcus, Pseudomonas, Oerskovia, Cell ulomonas, and Arthrobacter species. The chromosomal DNA patterns of the iso lates obtained by polymerase chain reaction (PCR) amplification of repetiti ve extragenic palindromic (REP) sequences were distinct from each other. Mo st of the isolates grew rapidly in 4-CBA medium, but their substrate utiliz ation capabilities were generally restricted. Plasmid DNAs were detected fr om 55% of the isolates, and one strain, HR7, was shown to have self-transmi ssible, 4-CBA degradative plasmids. 4-CBA degradative enzymes were inducibl e by the presence of 4-CBA and most of the isolates appeared to mineralize it through 4-hydroxybenzoate rather than 4-chlorocatechol. (C) 2000 Federat ion of European Microbiological Societies. Published by Elsevier Science B. V. All rights reserved.