Clostridium sediminicola sp. nov., a crude oil aggregation-forming anaerobic bacterium isolated from marine sediment.

A crude oil aggregation-forming, strictly anaerobic, Gram-stain-positive, spore-forming, rod-shaped, motile and mesophilic bacterium, named strain SH18-2^T, was isolated from marine sediment near Sado Island in the Sea of Japan. The temperature, salinity and pH ranges of this strain for the growth were 15-40 °C (optimum 35 °C), 0.5-6.0% NaCl (w/v; optimum 2.0%) and pH 6.0-8.0 (optimum 7.5), respectively. A phylogenetic analysis of the 16S rRNA gene sequence showed that this strain belongs to the genus Clostridium. It was most closely related to Clostridium grantii A-1^T (97.02% homology). The draft genome size was 5616089 bp, with a G+C content of 29.7 mol%. The digital DNA-DNA hybridization values determined using the Genome-to-Genome Distance Calculator and the average nucleotide identity between this strain and C. grantii A-1^T were 20.30 and 78.24%, respectively. Whole-organism hydrolysates of strain SH18-2^T contained meso-diaminopimelic acid; the major fatty acid was C_16:0, and the polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipid and three unidentified polar lipids. From the results of genotypic, phenotypic and chemotaxonomic analyses, SH18-2^T (=NBRC 116030^T=DSM 115762^T) is the type strain and represents a novel species of the genus Clostridium, and the name Clostridium sediminicola sp. nov. is proposed.