Deversity And Polyphasic Taxonomy Of Epiphytic Bacteria Isolated From Macroalgae

Eleven macroalgae samples belonging to three brown macroalgae Laminaria japonica Aresch,Sargassum natans L.and Colpomenia sinuosa(Mertens ex Roth)Derb.et Sol.were respectively collected from three different sea areas in Qingdao,Rongcheng,and Yantai.A total of 96 macroalgae epiphytic strains were then isolated from these samples using the 2216E medium and seawater R2A medium.To study the diversity of epiphytic bacteria of brown algae.The 16S r RNA gene sequence analysis revealed that these cultivable epiphytic bacteria belonged to forty-three genera of twenty-two families in four phyla.Among them,strains belonging to the phylum Proteobacteria was the most abundant,accounting for 67.7%of the total strains isolated,followed by those belonging to the phyla Bacteroidetes(18.8%)and those belonging to the phyla Firmicutes(10.4%)and Actinobacteria(3.1%).All Proteobacteria strains belonged to 24 genera,of which Pseudoalteromonas and Vibrio were the dominant genera,accounting for 13.54%and 9.38%of the total strains isolated,respectively;other genera were Marinomonas,Psychromonas,Shewanella,Sulfitobacter,Paraglaciecola,Colwellia,Alteromonas,Arenicella,Yoonia,Aliiglaciecola,Paracoccus,Acinetobacter,Altererythrobacter,Cobetia,Enterovibrio,Erythrobacter,Loktanella,Octadecabacter,Photobacterium,Pseudomonas,Psychrobacter and Sphingorhabdus.All Bacteroidetes strains belonged to 12 genera including Olleya,Algibacter,Flaviramulus,Lacinutrix,Maribacter,Arcticibacterium,Nonlabens,Tenacicaculum,Winogradskyella,Wenyingzhuangia,Pseudotenacibaculum and Kordia.All Firmicutes strains belonged to 5 genera including Bacillus,Chryseomicrobium,Halobacillus,Terribacillus and Salinicoccus.All Actinobacteria strains belonged to 2 genera,Brachybacterium and Micrococcus.The ability to degrade sodium alginate of some epiphytic bacterial strains isolated was also further tested.15genera have degradability,as follows:Aliiglaciecola?Algibacter?Flaviramulus?Sulfitobacter?Colwellia?Sphingomonas?Vibrio?Polaribacter?Pseudoalteromonas?Marinomonas?Halobacillus?Microbulbifer?Bacillus?Piscibacillus and Paraglaciecola.Strain SM1966~T,isolated from macroalgae surface Ulva pertusa L.samples of the aquaculture area of Rongcheng,was taxonomically characterized using a polyphasic taxonomic apporach incuded phenotypicc characterization and phylogenetic analysis.Strain SM1966~T was a Gram-stain-negative,aerobic bacterium.It grew at 5-55? and with 0-14.0%(w/v)Na Cl and hydrolyzed Tween 80 but not DNA and starch.Phylogenetic analysis of 16S r RNA gene sequences revealed that strain SM1966~Tbelonged to the genus Marinomonas,sharing 92.9-96.7%,16S r RNA gene sequence similarities to recognized Marinomonas species.The phylogenetic trees based on 16S r RNA gene sequences showed that strain SM1966~T,together with Marinomonas blandensis,formed a distinct phylogenetic branch within the cluster,of the genus Marinomonas.Polyphasic data presented here indicated that strain SM1966~T might represent a novel species of the genus Marinomonas.