Paracoccus halophilus sp. nov., isolated from marine sediment of the South China Sea, China, and emended description of genus Paracoccus Davis 1969

An aerobic bacterial isolate, strain HN-182(T), was isolated from sediments of the South China Sea. Cells of strain HN-182(T) are coccoid to short rods, Gram-negative, non-spore-forming and non-motile. Strain HN-182(T) is heterotrophic and grows well on marine broth (Difco 2216), and is not capable of growing autotrophically on reduced sulfur. Grows at temperatures ranging from 7 to 42 degrees C (optimum at 25 degrees C), but not at 4 or 45 degrees C, and at pH 5.0-9.0 (optimum at pH 7.0), but not at pH 4.5 or 9.5. NaCl is required for growth [0.5-8.5% (w/v)] with an optimum of 4.5%. Cells are positive for catalase, oxidase and urease activities. Nitrate is not reduced. Strain HN-182(T) contains ubiquinone-10 as sole respiratory quinone. The major polar lipids are phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid and an unidentified glycolipid. Major cellular fatty acids are C18:1omega7c (60.7 %), C16:0 (12.5%) and C18:0 (8.1%). DNA G+C content is 67.2 mol% (by T(m)). The analysis of 16S rRNA gene sequences indicated that strain HN-182(T) was related to members of the genus Paracoccus, with similarities ranging from 91.2 to 96.7% (highest to Paracoccus versutus) and a close relationship with Paracoccus sulfuroxidans, indicating that strain HN-182(T) is a member of Paracoccus. Based on these results, it is concluded that strain HN-182(T) represents a novel species of the genus Paracoccus, for which the name Paracoccus halophilus sp. nov. is proposed. The type strain is HN-182(T) (=CGMCC 1.6117(T)=JCM 14014(T)).