Siccirubricoccus phaeus sp. nov., isolated from oil reservoir water and emended description of the genus Siccirubricoccus

Abstract

A Gram-staining-negative, non-motile, aerobic bacterium, designated 1–3^T, was isolated from oil reservoir water collected from Liaohe oilfield, north-east of China. Growth was observed at 15–40 °C (optimum 37 °C) and pH 6–10 (optimum 7). The strain can grow under nitrogen-limiting condition. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate was most closely related to Siccirubricoccus deserti SYSU D8009^T (96.7%), followed by Paracraurococcus ruber NS89^T (95.7%) and Belnapia rosea CPCC 100156^T (94.9%). Genome sequencing revealed a genome size of 6.43 Mbp and a G+C content of 71.3 mol%. The average nucleotide identity values and digital DNA–DNA hybridization between 1–3^T and the reference strains were all below the cut-off level (95–96% and 70%, respectively) for species delineation. The strain possessed the cytochrome P450 enzyme, which has the potential to degrade oil. The respiratory quinone was Q-10 and the major fatty acids were summed feature 8 (C_18:1 ω7c/C_18:1 ω6c, 38.8%), C_16:0 (25.6%) and C_19:0 cyclo ω8c (22.5%). The polar lipids of strain 1–3^T comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and three unidentified aminolipids. Based on the genotypic and phenotypic characteristics, strain 1–3^T represents a novel species of genus Siccirubricoccus, for which the name Siccirubricoccus phaeus sp. nov. is proposed. The type strain of Siccirubricoccus phaeus is 1–3^T (= CGMCC 1.16799^T = LMG 31398^T).