Thauera lacus sp. nov., isolated from a saline lake in Inner Mongolia

A Gram-stain-negative, facultatively anaerobic, motile and rod-shaped bacterium, designated D20^T, was isolated from the saline Lake Dai in Inner Mongolia, PR China. Growth of strain D20^T occurred at 25-45 °C (optimum, 40 °C), pH 4.0-12.0 (optimum, 8.0) and with 0-3 % NaCl (w/v); (optimum, 0-1 %). The results of 16S rRNA gene sequence analysis revealed that strain D20^T was most closely related to three Thauera species, Thaueraselenatis AX^T, Thaueraaminoaromatica S2^T and Thaueraaromatica K172^T, with a similarity value of 96.2 %. The major respiratory quinone of strain D20^T was ubiquinone-8 (Q-8), and the dominant fatty acids (>10 %) were summed feature 3 (C_16 : 1ω6c and/or C_16 : 1ω7c; 39.8 %), C_16 : 0 (30.9 %) and summed feature 8 (C_18 : 1ω6c and/or C_18 : 1ω7c; 13.5 %). The polar lipid profile contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, one aminophospholipid and five unidentified lipids. The DNA G+C content was 67.2 mol% (data from the genome sequence). The estimated genome size was 3.7 Mb. The phenotypic, genotypic and chemotaxonomic differences between strain D20^T and its phylogenetic relatives indicated that strain D20^T should be regarded as a novel species in the genus Thauera, for which the name Thaueralacus sp. nov. is proposed. The type strain is D20^T (=MCCC 1H00305^T=KCTC 62586^T).