Paraconexibacter algicola gen. nov., sp. nov., a novel actinobacterium isolated from a eutrophic lake during the end of cyanobacterial harmful algal blooms, and proposal of Paraconexibacteraceae fam. nov. in the order Solirubrobacterales

A novel bacterium, strain Seoho-28 , was isolated from a shallow eutrophic lake during the end of cyanobacterial harmful algal blooms and was characterized taxonomically and phylogenetically. Strain Seoho-28 was a Gram-stain-negative, aerobic, rod-shaped and non-motile bacterium. The strain grew optimally with 0 % NaCl and at 25-30 °C on Reasoner's 2A medium. The phylogenetic analysis based on 16S rRNA gene sequences positioned the novel strain among the order , but sequence similarities to known species were less than 94.7 %. The genomic DNA G+C content of the strain Seoho-28 was 74.2 mol%. Genomic comparisons of strain Seoho-28 with families in the order were made using the Genome-to-Genome Distance Calculator, average nucleotide identity and average amino acid identity analyses (values indicated ≤14.9, ≤73.5 and ≤57.8 %, respectively). Strain Seoho-28 contained C -iso, C 9 and C as major fatty acids and MK-7 (H ) as the major quinone. Strain Seoho-28 contained diphosphatidylglycerol, phosphatidylinositol and an unidentified phospholipid as major polar lipids. - and ll-diaminopimelic acids were the diagnostic diamino acids in the cell-wall peptidoglycan. Based on the genotypic, chemotaxonomic and phenotypic results, strain Seoho-28 represents a novel genus and species, gen. nov., sp. nov., which belongs to a new family in the order and the class . The type strain is Seoho-28 (=KCTC 39791 =JCM 31881 ).