Description of Catellibacterium caeni sp. nov., reclassification of Rhodobacter changlensis Anil Kumar et al. 2007 as Catellibacterium changlense comb. nov. and emended description of the genus Catellibacterium Jin-Wei Zheng, 1 3 Yi-Guang Chen, 2,3 3 Jun Zhang, 1 Ying-Ying Ni, 1 Wen-Jun Li, 2,4 Jian He 1 and Shun-Peng Li 1 Correspondence Wen-Jun Li wjli@ynu.edu.cn Jian He hejian@njau.edu.cn 1 Key Laboratory for Microbiological Engineering of Agricultural Environment of Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China 2 Key Laboratory of Microbial Diversity in Southwest China Ministry of Education, Yunnan Institute of Microbiology, Yunnan University, Kunming 650091, PR China 3 College of Biology and Environmental Science, Jishou University, Jishou 416000, PR China 4 Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China A novel non-sporulating, non-motile, catalase- and oxidase-positive, strictly aerobic, Gram-negative, rod-shaped bacterial strain, designated DCA-1 T , was isolated from activated sludge collected from a butachlor wastewater treatment facility. The strain was able to degrade about 85 % of 100 mg butachlor l ”1 within 5 days of incubation. Growth occurred in the presence of 0–6 % (w/v) NaCl [optimum, 1 % (w/v) NaCl] and at pH 5.5–9.0 (optimum, pH 7.0) and 15–35 6C (optimum, 25–30 6C). Vesicular internal membrane structures and photoheterotrophic growth were not observed. The major respiratory quinone was ubiquinone 10 (Q-10) and the major cellular fatty acids were C 18 : 1 v7c and 11-methyl C 18 : 1 v7c. The genomic DNA G+C content of strain DCA-1 T was 62.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain DCA-1 T was a member of the family Rhodobacteraceae and was related most closely to the type strain of Catellibacterium aquatile (96.5 % sequence similarity). The combination of phylogenetic analysis, phenotypic characteristics and chemotaxonomic data supports the suggestion that strain DCA-1 T represents a novel species of the genus Catellibacterium, for which the name Catellibacterium caeni sp. nov. is proposed. The type strain is DCA-1 T (5CGMCC 1.7745 T 5DSM 21823 T ). In addition, based on the characterization data obtained in this study, it is proposed that Rhodobacter changlensis should be reclassified as Catellibacterium changlense comb. nov. (type strain JA139 T 5DSM 18774 T 5CCUG 53722 T 5JCM 14338 T ). An emended description of the genus Catellibacterium is also presented. The genus Catellibacterium, belonging to the family Rhodobacteraceae, was first proposed by Tanaka et al. (2004) with the description of Catellibacterium nectariphilum. Recently, a second species, Catellibacterium aquatile, was proposed by Liu et al. (2010), with an emended description of the genus. During an investigation of the microbial diversity of a butachlor [N-(butoxymethyl)-2-chloro-N-(2,6-diethyl- phenyl)acetamide] wastewater treatment facility in Jiangsu Province, China, a butachlor-degrading, Gram-negative bacterium, designated strain DAC-1 T , was isolated from activated sludge. Based on the results of a polyphasic taxonomic study, this strain is considered to represent a novel species of the genus Catellibacterium. Strain DCA-1 T was isolated from an activated sludge sample by plating 1 : 10 serial dilutions of the sample on Luria– Bertani (LB) agar (Atlas & Parks, 1993) supplemented with 3These authors contributed equally to this work. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain DCA-1 T is FJ386516. Three supplementary figures are available with the online version of this paper. International Journal of Systematic and Evolutionary Microbiology (2011), 61, 1921–1926 DOI 10.1099/ijs.0.025494-0 025494 G 2011 IUMS Printed in Great Britain 1921