Scopulibacillus daqui sp. nov., a thermophilic bacterium isolated from high temperature daqu

A Gram-stain-positive, facultatively anaerobic, thermophilic bacterium, designated ZQ18-1T, was isolated from a high temperature daqu sample collected from the sesame-flavour liquor-making process. Oval endospores were formed at the centre of cells with swollen sporangia. The isolate was able to grow at temperatures of 20-60 °C (optimum growth at 50 °C), at pH 4-9 (optimum growth at pH 8) and in the presence of 0-10 % (w/v) NaCl (optimum growth with 2 % NaCl). Glucose and galactose were major cell-wall sugars, and meso-diaminopimelic acid was the diagnostic amino acid. The major polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol and three glycolipids. The major cellular fatty acids were anteiso-C17 : 0 and iso-C16 : 0, and the predominant menaquinone was MK-7. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ZQ18-1T was most closely related to Scopulibacillus darangshiensis DLS-06T, Pullulanibacillus pueri YN3T, Tuberibacillus calidus 607T, Pullulanibacillus naganoensis ATCC 53909T, Pullulanibacillus uraniitolerans UG-2T, Sporolactobacillus terrae DSM 11697T and Sporolactobacillus inulinus NRIC 1133T. Strain ZQ18-1T showed low DNA-DNA relatedness (40.7, 23.1, 46.5, 27.2, 45.6, 33.7 and 55.1 %) with the strains mentioned above. Based on morphological characteristics, chemotaxonomic characteristics, DNA-DNA hybridization data and physiological properties, strain ZQ18-1T represents a novel species of the genus Scopulibacillus, for which the name Scopulibacillus daqui sp. nov. is proposed. The type strain is Scopulibacillus daqui ZQ18-1T (=DSM 28236T=CICC 10824T). An emended description of the genus Scopulibacillus is provided.