title: [Isolation, identification and characterization of an agarase-producing marine bacterial strain Stenotrophomonas sp. NTa].
abstract: OBJECTIVE
  To identify and characterize a marine bacterial strain producing agarase.
  
  
  METHODS
  The agarase-producing bacterium was isolated from coastal sediments in Xiamen using agar as the sole carbon source. The strain was identified by the analyses of 16S rRNA gene sequence, phenotype and biochemical reactions. Agarase activity was determined by dinitrosalicylic acid method, and the category of agarase was assayed using chromogenic substrate. At last, the characteristics of agarase were determined.
  
  
  RESULTS
  The results of the 16S rRNA phylogenetic, phenotypic and biochemical analyses showed that: the agar-degrading bacterium NTa belonged to the genus Stenotrophomonas sp.. The strain could produce extracellular agarases, including alpha-agarase and beta-agarase. The optimum temperature and pH of strain NTa agarase were 40 degrees C and 7.0, respectively. The enzymatic activity was stable below 30 degrees C. It also showed stability over a pH range between 7.0 and. 0. Ca2+ could activate agarase activity, and Na+, K+ and Mg2+ had no significant influence. However, Ag', Ba2 , Fe2' , Mn2', Cu2', Zn2+ and Fe3' inhibited the enzyme activity. The enzymatic activity of stain NTa agarase was inhibited by EDTA. The agarase had good resistance to some inhibitors, detergents and denaturant.
  
  
  CONCLUSIONS
  Stenotrophomonas sp. NTa is a new type of agarase-producing strain, which can produce both alpha-agarase and beta-agarase and has potential applications in the production of agaro-oligosaccharide.
authors.forename: Ruiping
authors.initials: R
authors.lastname: Ma
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Zhu
authors.forename: Hui
authors.initials: H
authors.lastname: Ni
authors.forename: Hedong
authors.initials: H
authors.lastname: Luo
authors.forename: Anfeng
authors.initials: A
authors.lastname: Xiao
authors.forename: Huinong
authors.initials: H
authors.lastname: Cai
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*; D020588:Stenotrophomonas / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D006026:Glycoside Hydrolases; C019624:agarase