Paracoccus contaminans sp. nov., isolated from a contaminated water microcosm.

A beige-pigmented, oxidase-positive bacterial strain (WPAn02T), isolated as a presumably airborne contaminant of an axenic bacterial microcosm, was studied using a polyphasic taxonomic approach. Cells of the isolate were coccoid and stained Gram-negative. A comparison of the 16S rRNA gene sequence of strain WPAn02T with sequences of type strains of the most closely related species of the genus Paracoccus showed highest sequence similarities to Paracoccus chinensis (97.7 %), Paracoccus marinus (97.1 %), Paracoccus niistensis (97.4 %) and 'Paracoccus zhejiangensis' (97.0 %). 16S rRNA gene sequence similarities to all other species of the genus Paracoccuswere below 97 %. The fatty acid profile of the strain consisted of the major fatty acids C18 : 1ω7c/ω9t/ω12t and C18 : 0. DNA-DNA hybridizations between WPAn02T and type strains of P. chinensis, P. marinus, P. niistensis, and 'P. zhejiangensis' resulted in similarity values of 49 % (reciprocal 22 %), 16 % (reciprocal 10 %), 30 % (reciprocal 32 %), and 18 % (reciprocal 7 %), respectively. DNA-DNA hybridization results together with the differentiating biochemical and chemotaxonomic properties indicated that WPAn02T represents a novel species of the genus Paracoccus, for which the name Paracoccus contaminans sp. nov. (type strain WPAn02T=RKI 16-01929T=LMG 29738T=CCM 8701T=CIP 111112T), is proposed.