Trichococcus shcherbakoviae sp. nov., isolated from a laboratory-scale anaerobic EGSB bioreactor operated at low temperature.

A new species of the genus Trichococcus, strain Art1, was isolated from a psychrotolerant syntrophic propionate-oxidizing consortium, obtained before from a low-temperature EGSB reactor fed with a mixture of VFAs (acetate, propionate and butyrate). The 16S rRNA gene sequence of strain Art1 was highly similar to those of other Trichococcus species (99.7-99.9 %) but digital DNA-DNA hybridization values were lower than those recommended for the delineation of a novel species, indicating that strain Art1 is a novel species of the genus Trichococcus. Cells of strain Art1 are non-motile cocci with a diameter of 0.5-2.0 µm and were observed singularly, in pairs, short chains and irregular conglomerates. Cells of Art1 stained Gram-positive and produced extracellular polymeric substances . Growth was optimal at pH 6-7.5 and cells could grow in a temperature range of from -2 to 30 °C (optimum 25-30 °C). Strain Art1 can degrade several carbohydrates, and the main products from glucose fermentation are lactate, acetate, formate and ethanol. The genomic DNA G+C content of strain Art1 is 46.7 %. The major components of the cellular fatty acids are C16 : 1 ω9c, C16 : 0 and C18 : 1 ω9c. Based on genomic and physiological characteristics of strain Art1, a new species of the genus Trichococcus, Trichococcusshcherbakoviae, is proposed. The type strain of Trichococcusshcherbakoviae is Art1 (=DSM 107162 = VKM B-3260).