Chryseomicrobium aureum sp. nov., a bacterium isolated from activated sludge.

A Gram-stain-positive, rod-shaped, non-motile, non-spore-forming, aerobic bacterial strain, designated BUT-2(T), was isolated from activated sludge of one herbicide-manufacturing wastewater-treatment facility in Kunshan, Jiangsu province, China, and subjected to polyphasic taxonomic studies. Analysis of the 16S rRNA gene sequence indicated that strain BUT-2(T) shared the highest similarity with Chryseomicrobium amylolyticum (98.98%), followed by Chryseomicrobium imtechense (98.88%), with less than 96% similarlity to members of the genera Paenisporosarcina, Planococcus, Sporosarcina and Planomicrobium. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain BUT-2(T) clustered with C. amylolyticum JC16(T) and C. imtechense MW10(T), occupying a distinct phylogenetic position. The major fatty acid (>10% of total fatty acids) type of strain BUT-2(T) was iso-C(15 : 0). The quinone system comprised menaquinone MK-7 (77.8%), MK-6 (11.9%) and MK-8 (10.3%). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and some unidentified phospholipids. The cell-wall peptidoglycan type of strain BUT-2(T) was L-Orn-D-Glu. The genomic DNA G+C content of strain BUT-2(T) was 48.5 mol%. Furthermore, the DNA-DNA relatedness in hybridization experiments against the reference strain was lower than 70%, confirming that strain BUT-2(T) did not belong to previously described species of the genus Chryseomicrobium. On the basis of its morphological, physiological and chemotaxonomic characteristics as well as phylogenetic analysis, strain BUT-2(T) is considered to represent a novel species of the genus Chryseomicrobium, for which the name Chryseomicrobium aureum sp. nov. is proposed. The type strain is BUT-2(T) ( = CCTCC AB2013082(T) = KACC 17219(T)).