Paracoccus siganidrum sp. nov., isolated from fish gastrointestinal tract.

A bacterial strain, designated M26(T), was isolated from a fish gastrointestinal tract, collected from Zhanjiang Port, South China. 16S rRNA gene sequence analysis indicated that strain M26(T) belongs to the subclass α-Proteobacteria, being related to the genus Paracoccus, and sharing highest sequence similarity with Paracoccus alcaliphilus JCM 7364(T) (98.1 %), Paracoccus huijuniae FLN-7(T) (97.3 %), Paracoccus stylophorae KTW-16(T) (97.1 %) and Paracoccus seriniphilus DSM 14827(T) (96.9 %). The major quinone was determined to be ubiquinone Q-10, with Q-9 and Q-8 as minor components. The major fatty acid was identified as C18:1ω7c, with smaller amounts of C18:0 and C16:0. The G+C content of the genomic DNA was determined to be 64.3 mol%. The DNA hybridization value between strain M26(T) and the most closely related type strain, P. alcaliphilus, was 29.0 ± 1.0 %. The results of physiological and biochemical tests and low DNA-DNA relatedness showed that the strain could be readily distinguished from closely related species. On the basis of these phenotypic and genotypic data, strain M26(T) is concluded to represent a novel species of the genus Paracoccus, for which the name Paracoccus siganidrum sp. nov. is proposed. The type strain is M26(T) (=CCTCC AB 2012865(T) = DSM 26381(T)).