Crassaminicella indica sp. nov., a novel thermophilic anaerobic bacterium isolated from a deep- sea hydrothermal vent

A novel moderately thermophilic heterotrophic bacterium, designated strain 143-21T, was isolated from a deep -sea hydro-thermal chimney sample collected from the Central Indian Ridge at a depth of 2 440 m. Phylogenetic analysis indicated that strain 143-21T belongs to the genus Crassaminicella. It was most closely related to Crassaminicella thermophila SY095T (96.79% 16S rRNA gene sequence similarity) and Crassaminicella profunda Ra1766HT (96.52 %). Genomic analysis showed that strain 143-21T shares 79.79-84.45 % average nucleotide identity and 23.50-29.20 % digital DNA-DNA hybridization with the species of the genus Crassaminicella, respectively. Cells were rod-shaped, non-motile, Gram- positive-staining. Terminal endospores were observed in stationary -phase cells when strain 143-21T was grown on Thermococcales rich medium. Strain 143-21T was able to grow at 30-60 & DEG;C (optimum, 50 & DEG;C), pH 6.5-8.5 (optimum, pH 7.0) and in 1.0-7.0 % NaCl (w/v; optimum 2.0 %, w/v). Strain 143-21T utilized fructose, glucose, maltose, mannose, ribose, N-acetyl -o-(+)-glucosamine and casamino acids, as well as amino acids including glutamate, lysine, histidine and cysteine. The main fermentation products from glucose were acetate (2.07 mM), H2 and CO2. It did not reduce elemental sulphur, sulphate, thiosulphate, sulphite, fumarate, nitrate, nitrite and Fe (III). The pre-dominant cellular fatty acids were C14: 0 (48.8 %), C16: 0 (12.9 %), and summed feature 3 (C16:1 & omega;7c and/or C16:1 & omega;6c; 10.2 %). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, as well as two unidenti-fied phospholipids and four unidentified aminolipids. No respiratory quinones were detected. Based on its phylogenetic analysis and physiological characteristics, strain 143-21T is considered to represent a novel species of the genus Crassaminicella, for which the name Crassaminicella indica sp. nov. is proposed. The type strain is strain 143-21T (=DSM 114408T= MCCC 1K06400T).

Automated summary

A novel moderately thermophilic bacterium, strain 143-21T, was isolated from a deep-sea hydrothermal chimney sample. It belongs to the genus Crassaminicella and shows high similarity to Crassaminicella thermophila SY095T and Crassaminicella profunda Ra1766HT. The strain has a wide temperature, pH, and salinity tolerance and can utilize various carbon sources and amino acids for growth, producing acetate, H2, and CO2 as fermentation products. Based on its phylogenetic analysis and physiological characteristics, it is proposed as a new species named Crassaminicella indica sp. nov.