A Gram-stain-positive, aerobic, endospore-forming and rod-shaped bacterium (KQ-3T), which grew at 10-45 °C (optimum 35 °C), pH 8.0-10.5 (optimum pH 9.0) and in the presence of 0-16 % (w/v) NaCl (optimum 3.0 %), was isolated from a soda lake and identified as representing a novel species using a polyphasic taxonomic approach. Strain KQ-3T was catalase-positive, oxidase-negative and non-motile. Phylogenetic analysis based on 16S rRNA gene sequence affiliated KQ-3T to the genus Alteribacter and showed the highest similarities to Alteribacter natronophilus M30T (97.90 %), Alteribacter aurantiacus K1-5T (97.84 %) and Alteribacter populi FJAT-45347T (97.22 %). Digital DNA-DNA hybridization and average nucleotide identity analyses revealed that KQ-3T displayed 21.4 and 72.81% genomic DNA relatedness with the most closely related strain, A. natronophilus M30T, respectively. KQ-3T contained all of the conserved signature indels that are specific for members of the genus Alteribacter. The DNA G+C content was 45.03 mol%. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and one unidentified phospholipid. The predominant menaquinone was MK-7 (100%) and the major fatty acids (>10 %) comprised anteiso-C15 : 0, iso-C15 : 0 and iso-C16 : 0. Based on the data from the current polyphasic studies, KQ-3T represents a novel species of the genus Alteribacter, for which the name Alteribacter keqinensis sp. nov. is proposed. The type strain is KQ-3T (=ACCC 61799T=KCTC 33933T).
Keywords: Alteribacter; Alteribacter keqinensis sp. nov.; alkaliphile; conserved signature indel; moderately halophilic; soda lake.