Winogradskyella immobilis sp. nov., an Alginate-Hydrolyzing Bacterium Isolated from the Brown Algae Saccharina japonica.

A novel bacterium, designated E313 T , was isolated from brown algae Saccharina japonica in Weihai, China. The strain is a Gram-stain-negative, non-flagellated, non-gliding, aerobic, rod-shaped bacterium that grows optimally at 28 °C with pH levels between 7.0 and 7.5 and in the presence of 2-3% (w/v) NaCl. Phylogenetic analyses based on its 16S rRNA gene sequence placed the strain within the monophyletic cluster of the genus Winogradskyella, exhibiting the highest similarity to Winogradskyella wandonensis KCTC 32579 T (96.8%). Genome comparison of strain E313 T with W. wandonensis KCTC 32579 T and W. thalassocola KCTC 12221 T revealed average nucleotide identity (ANI) values of 74.2% and 74.8%, and DNA-DNA hybridization (dDDH) values of 19.0% and 19.5%, respectively, lower than prokaryotic species delineation values. The strain E313 T could hydrolyze alginate. A total of 123 carbohydrate-active enzymes were annotated according to the CAZy database. Especially, one oligo-alginate lyase and one poly(β-D-mannuronate) lyase were identified in the genome of strain E313 T . Strain E313 T possessed MK-6 quinone and iso-C 15:0 , iso-C 15:1 G, iso-C 17:0 3-OH, and iso-C 15:0 3-OH as main fatty acids. Its major polar lipids were phosphatidylethanolamine (PE), one unidentified aminolipid, and two unknown lipids. Thus, based on phylogenetic, physiological, and chemotaxonomic analyses, we propose a novel species of the genus Winogradskyella, named Winogradskyella immobilis sp. nov., with E313 T (= MCCC 1H00506 T  = KCTC 82731 T ) as the type strain.