Rhodococcus koreensis sp. nov., a 2,4-dinitrophenol-degrading bacterium.

Abstract

A 2,4-dinitrophenol-degrading bacterial strain, DNP505 T , which was isolated from an industrial wastewater, was taxonomically studied by a polyphasic approach using phenotypic, chemotaxonomic and genetic methods. Strain DNP505T has a cell wall of chemotype IV containing meso-diaminopimelic acid, arabinose and galactose. The predominant menaquinone is MK-8(H 2 ). Mycolic acids contain 43-53 carbon atoms. Strain DNP505T has a cellular fatty acid profile containing straight-chain saturated, unsaturated and 10-methylbranched fatty acids and has C 16 :0 as the major fatty acid. The DNA GMC content is 66 mol %. Strain DNP505T formed a coherent cluster with Rhodococcus species in a phylogenetic inference based on 16S rDNA sequences. Interestingly, strain DNP505T was found to have two types of 16S rDNA sequence, which showed 10 bp sequence differences (993 % nucleotide similarity). Its differences in some phenotypic characteristics and its genetic distinctiveness indicate that strain DNP505T is separate from Rhodococcus species described previously. It is therefore proposed that strain DNP505 Keywords : Rhodococcus koreensis sp. nov., 2,4-dinitrophenol degradation, polyphasic taxonomy INTRODUCTIONNitroaromatic compounds are frequently used as building blocks for dyes, plastics, explosives, herbicides and pesticides, and are also important as solvents (Lenke et al., 1992 ;Marvin-Sikkema & de Bont, 1994). However, despite their industrial importance, nitroaromatic compounds are in most cases highly toxic to living organisms, including microorganisms. They are abundantly present in nature and, in particular, are found as contaminants in waste waters, rivers and herbicide-or pesticide-treated soils (Lenke et al., 1992 ;Marvin-Sikkema & de Bont, 1994). In spite of the toxicity of nitroaromatic compounds, several micro-organisms that are able to convert or degrade nitroaromatic compounds have been found to exist in nature (Marvin-Sikkema & de Bont, 1994 aromatic-contaminated sites (Bruhn et al., 1987 ;Cho et al., 1998 ;Zeyer & Kearney, 1984).2,4-Dinitrophenol is a well known toxic aromatic compound. It causes toxicity by uncoupling oxidative phosphorylation in the mitochondria of cells (Ilvicky & Casida, 1969 ;Simon, 1953). It causes ' dinitrophenol poisoning ' to man exposed to contaminated environments (Leftwich et al., 1982). The classic syndrome of ' dinitrophenol poisoning ' includes lassitude, malaise, headache, increased perspiration, thirst, profound weight loss and respiratory failure (Leftwich et al., 1982). Some bacterial strains have been reported to degrade 2,4-dinitrophenol (Hess et al., 1990 ;Lenke et al., 1992). Such useful strains utilizing 2,4-dinitrophenol as sole carbon and nitrogen sources have been isolated in our laboratory. Among them, one strain (DNP505) was found to have high ability to utilize or degrade 2,4-dinitrophenol and was considered to be a member of the genus Rhodococcus. The aim of this study was to determine the exact phylogenetic position of strain DNP505. We describe its morphological ...

Degradation of Estrogens by Rhodococcus zopfii and Rhodococcus equi Isolates from Activated Sludge in Wastewater Treatment Plants

“…In addition, Rhodococcus sp. strains found in the present study have been reported to degrade cholesterol that possesses a steroidal skeleton and to degrade aromatic compounds and aniline as well as environmental pollutants such as 2,4-dinitrophenol, polychlorinated biphenyl, and 2,4,6-trichlorophenol, which are difficult to degrade (19,25,30,34,36). We consider that some species of the genus Rhodococcus may possess an enzyme system that degrades the steroidal skeleton.…”

Rare Branched Fatty Acids Characterize the Lipid Composition of the Intra-Aerobic Methane Oxidizer “Candidatus Methylomirabilis oxyfera”

“…10MeC 16:0 FA has been proposed to be characteristic of sulfatereducing bacteria (SRB) of the genera Desulfobacter and Desulfobacula, where it is found to make up various amounts of approximately 5 to 25% of the total lipids (4,15,32,33,45,51). Besides these sulfate reducers, 10MeC 16:0 FA is also occasionally, but generally in much smaller amounts, found in other bacteria; the literature reports its presence in several actinobacteria (6,12,23,31,41,56,58), in anammox bacteria and other planctomycetes (48,49), in an iron-reducing Geobacter species (34,57), in a Marinobacter species (55), and in the marine denitrifier Pseudomonas nautica (14). Several studies report the presence of 10MeC 16:0 FA in relation to the occurrence of anaerobic methane oxidation (AOM) coupled to sulfate reduction (1,2,7,17,26,39).…”

Rhodococcus defluvii sp. nov., isolated from wastewater of a bioreactor and formal proposal to reclassify [Corynebacterium hoagii] and Rhodococcus equi as Rhodococcus hoagii comb. nov.

“…nov. with strain Ca11 T as a representative type strain. The phylogenetic analysis based on nearly full-length 16S rRNA gene sequence analysis indicated that the R. equi 16S rRNA gene clade, including R. equi, R. kunmingensis, and strain Ca11 T represents a separate phylogenetic lineage, but assignment to the genus Rhodococcus remained, because no distinct chemotaxonomic differences were found to justify a reclassification and the proposal of a (Helmke & Weyland, 1984;Zhang et al, 2002Zhang et al, , 2005Klatte et al, 1994;Briglia et al, 1996;Yoon et al, 2000;Goodfellow et al, 2002;Takeuchi et al, 2002;Matsuyama et al, 2003;Li et al, 2004). +, Positive; W, weakly positive; 2, negative.…”