show Abstracthide AbstractBrown algae (seaweed) is abundant carbon resource. For effective utilization of the biomass, mechanism of decomposition is need to be elucidated. We focused on bacteria that colonize on the algae and degrade polysaccharide laminarin and alginate, which are highly contained in brown algae. Brown algae Undaria (seaweed)-containing seawater were incubated with laminarin-minimum media, followed by isolation of grown bacterium. Genomic DNA of the isolate was sequenced by Illumina Novoseq X.