Paracoccus onubensis sp. nov., a novel alphaproteobacterium isolated from the wall of a show cave

Abstract

A novel facultatively anaerobic, non-motile, Gram-stain-negative, non-endospore-forming alphaproteobacterium, strain 1011MAR3C25T, was isolated from a white biofilm colonizing the walls of the Andalusian show cave Gruta de las Maravillas (Huelva, Spain). Strain 1011MAR3C25T grew at 8–42 °C (optimum, 20–30 °C), at pH 5.0–9.0 (optimum, pH 5.0–6.0) and in the presence of 0–12 % (w/v) NaCl (optimum 3–5 %). Cells were catalase- and oxidase-positive. The strain grew heterotrophically with various carbon sources and chemoautotrophically with thiosulfate under aerobic conditions. Results of phylogenetic analysis showed that strain 1011MAR3C25T was related to Paracoccus saliphilus DSM 18447T and Paracoccus alkanivorans LMG 30882T (97.90 % and 97.32 % 16S rRNA sequence identity values, respectively). The major respiratory quinone was ubiquinone Q-10 and the predominant fatty acid was C18 : 1 ω7c. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid, an unidentified glycolipid and an unidentified polar lipid. The DNA G+C content was 60.3 mol%. Based on a polyphasic taxonomic study it is proposed that strain 1011MAR3C25T (=CECT 9092T=LMG 29414T) represents a novel species of the genus Paracoccus , for which the name Paracoccus onubensis sp. nov. is proposed.