Alteribacter keqinensis sp. nov., a moderately halophilic bacterium isolated from a soda lake

Salipaludibacillus daqingensis sp. nov., a moderately halophilic bacterium isolated from an oilfield

A novel alkaliphilic, Gram-stain-positive, moderately halophilic, rod-shaped, endospore-forming, motile, facultatively anaerobic bacterium (DQ-9T) was isolated from a sediment sample collected from Daqing oilfield in China, and characterized by a polyphasic taxonomic approach. Strain DQ-9T formed yellow pigment and grew occurred at salinities of 1-12 % (w/v) NaCl (optimum, 8 %) and at 10-40 °C (optimum, 30-35 °C), at pH 7.5-10.5 (optimum, pH 9.0-9.5). It was catalase-positive, but oxidase-negative. Based on the analysis of 16S rRNA gene sequences, DQ-9T was classified into the genus Salipaludibacillus and exhibited the highest similarities (98.37 %) to Salipaludibacillus neizhouensis JSM 071004T. Digital DNA-DNA hybridization and average nucleotide identity values between strain DQ-9T and the most closely related strain, S. neizhouensis DSM 19794T, were determined to be 72.0 and 21.6 %, respectively. The polar lipids were constituted by diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids (>5 %) comprised anteiso-C15 : 0, anteiso-C17 : 0, iso-C17 : 0, iso-C15 : 0 and C16 : 0. The cell-wall peptidoglycan contained meso-diaminopimelic acid, and menaquinone-7 was identified as the primary respiratory quinone. The DNA G+C content was 37.5 mol%. Through chemotaxonomic, physiological, and biochemical characterization, strain DQ-9T could be clearly distinguished from the closest Salipaludibacillus species. Based on provided data, strain DQ-9T is proposed to represent a novel species, Salipaludibacillus daqingensis sp. nov., within the genus Salipaludibacillus. The type strain is DQ-9T (=ACCC 60415T=KCTC 33936T).

Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae

The subtilase family (S8), a member of the clan SB of serine proteases are ubiquitous in all kingdoms of life and fulfil different physiological functions. Subtilases are divided in several groups and especially subtilisins are of interest as they are used in various industrial sectors. Therefore, we searched for new subtilisin sequences of the family Bacillaceae using a data mining approach. The obtained 1,400 sequences were phylogenetically classified in the context of the subtilase family. This required an updated comprehensive overview of the different groups within this family. To fill this gap, we conducted a phylogenetic survey of the S8 family with characterised holotypes derived from the MEROPS database. The analysis revealed the presence of eight previously uncharacterised groups and 13 subgroups within the S8 family. The sequences that emerged from the data mining with the set filter parameters were mainly assigned to the subtilisin subgroups of true subtilisins, high-alkaline subtilisins, and phylogenetically intermediate subtilisins and represent an excellent source for new subtilisin candidates.