Flavihalobacter algicola gen. nov. sp. nov., a member of the family Flavobacteriaceae with alginate- degradation activity, isolated from marine alga Saccharina japonica

A Gram- stain-negative, aerobic, yellow, non-motile, rod-shaped and alginate-degrading bacterium, designated Dm15(T), was isolated from marine alga collected in Weihai, PR China. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Dm15(T) represents a distinct line of the family Flavobacteriaceae. Strain Dm15(T) had the highest 16S rRNA gene sequence similarity to its closest phylogenetic neighbour Arcticiflavibacter luteus (96.7 %) and 93.7?96.4 % sequence similarity to other phylogenetic neighbours (Bizionia paragorgiae, Winogradskyella thalassocola, Ichthyenterobacterium magnum, Psychroserpens burtonensis and Arcticiflavibacter luteus) in the family Flavobacteriaceae. The novel isolate was able to grow at 10?40 ?C (optimum, 30?33 degrees C), pH 7.0?9.0 (optimum, pH 7.0-7.5) and with 0.5-6.0 % NaCl (optimum 2.0-3.0 %, w/v). It could grow at 40 degrees C, and degrade alginate and cellulose, which were different from the neighbour genera. The draft genome consisted of 3395 genes with a total length of 3 798 431 bp and 34.1mol% G+C content. Especially, there were some specific genes coding for cellulase and alginate lyase, which provided a basis for the above phenotypic characteristics. The strain's genome sequence showed 71.1?80.2 % average amino acid identity values and 71.8?77.7 % average nucleotide identity values compared to the type strains of related genera within the family Flavobacteriaceae. It shared digital DNA?DNA hybridization identity of 19.8 and 20.9 % with I. magnum and A. luteus, respectively. The sole menaquinone was MK-6. The major fatty acids were iso- C15.0 and iso- C15.1 G. The polar lipids included six unidentified polar lipids, four unidentified aminolipids and phosphatidylethanolamine. Based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, strain Dm15T represents a novel species of a new genus in the family Flavobacteriaceae, phylum Bacteroidetes, for which the name Flavihalobacter algicola gen. nov., sp. nov. is proposed. The type strain is Dm15T (KCTC 42256T=CICC 23815T).

Automated summary

A novel Gram-negative bacterium, Flavihalobacter algicola gen. nov., sp. nov., designated Dm15(T), isolated from marine alga in Weihai, China, showed unique characteristics such as growth at a wide range of temperature and salinity, as well as the ability to degrade alginate. It represents a distinct lineage within the family Flavobacteriaceae, with specific genes for cellulase and alginate lyase contributing to its phenotypic characteristics.