Paracoccus everestensis sp. nov., a novel bacterium with great antioxidant capacity isolated from the north slope o Mount Everest

A bacterial strain, designated S8-55(T), was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 5500 m above sea level. The purpose of this study was to describe a novel species and its characteristics, through genome sequencing and analysis of the relationship between the members of the genus Paracoccus, and explore the antioxidant capacity of strain S8-55(T). The polyphasic study confirmed the affiliation of strain S8-55(T )with the genus Paracoccus. Strain S8-55(T )was aerobic, Gram-negative and oxidase- and catalase positive. Cells were orange-pigmented, ellipsoid and had no spore formation, no flagella and no motility. Strain S8-55(T) grow at 10-37 degrees C, pH 7-11 and without NaCl. Ubiquinone 10 was its predominant respiratory menaquinone. The polar lipids of strain S8-55(T) were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an unidentified phospholipid, an unidentified aminolipid and three unidentified lipids. Its major fatty acids were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c). The G+C content was 64.3 mol%. The phylogenetic analysis based on the 16S rRNA sequence showed that strain S8-55(T) was closely related to Paracoccus angustae E6(T) (97.9%), Paracoccus aerius 011410(T) (97.9%) and Paracoccus hibisci THG-T2.8(T) (97.8%). The average nucleotide identity values among strain S8-55(T) and P angustae CCTCC AB 2015056(T), P. aerius KCTC 42845(T) and P. hibisci CCTCC AB 2016181(T) were 84.1, 84.5 and 76.3%, respectively. The genome of strain S8-55(T) contained antioxidant genes such as oxyR, recD, katE, recD and rpoH. Based on its morphological, physiological and chemical taxonomic characteristics, strain S8-55(T) (=JCM 35227(T)=GDMCC 1.3026(T)) should be classified as a novel species of the genus Paracoccus with the proposed name Paracoccus everestensis sp. nov.