Sulfuriferula multivorans gen. nov., sp. nov., isolated from a freshwater lake, reclassification of ‘Thiobacillus plumbophilus’ as Sulfuriferula plumbophilus sp. nov., and description of Sulfuricellaceae fam. nov. and Sulfuricellales ord. nov.

Abstract

A sulfur-oxidizing bacterium, strain TTN(T), was isolated from a Thioploca sample obtained from a freshwater lake in Japan. The isolate shared 97.1% 16S rRNA gene sequence similarity with an obligately aerobic chemolithoautotroph, 'Thiobacillus plumbophilus' Gro7(T). Cells were rods, motile, and Gram-stain-negative. The G+C content of the genomic DNA was approximately 66 mol%. Strain TTN(T) grew over a temperature range of 8-32 °C (optimum 22-25 °C), an NaCl concentration range of 0-133.3 mM (optimum 0-3.3 mM) and a pH range of 5.3-8.6 (optimum pH 6.4-7.0). Strain TTN(T) was facultatively anaerobic and could utilize nitrate as an electron acceptor. The isolate oxidized tetrathionate, thiosulfate and elemental sulfur as the sole energy sources for autotrophic growth, and could also grow heterotrophically on a number of organic substrates. Based on its phylogenetic and phenotypic properties, strain TTN(T) represents a novel species of a novel genus, for which the name Sulfuriferula multivorans gen. nov., sp. nov. is proposed. The type strain is TTN(T) ( =NBRC 110683(T) =DSM 29343(T)). Along with this, the reclassification of 'Thiobacillus plumbophilus' as Sulfuriferula plumbophilus sp. nov. (type strain Gro7(T) =NBRC 107929(T) =DSM 6690(T)) is proposed. Based on the data obtained in this study, we describe the designations Sulfuricellaceae fam. nov. and Sulfuricellales ord. nov.