title: Purification and characterization of cold-adapted beta-agarase from an Antarctic psychrophilic strain.
abstract: An extracellular β-agarase was purified from Pseudoalteromonas sp. NJ21, a Psychrophilic agar-degrading bacterium isolated from Antarctic Prydz Bay sediments. The purified agarase (Aga21) revealed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular weight of 80 kDa. The optimum pH and temperature of the agarase were 8.0 and 30 °C, respectively. However, it maintained as much as 85% of the maximum activities at 10 °C. Significant activation of the agarase was observed in the presence of Mg(2+), Mn(2+), K(+); Ca(2+), Na(+), Ba(2+), Zn(2+), Cu(2+), Co(2+), Fe(2+), Sr(2+) and EDTA inhibited the enzyme activity. The enzymatic hydrolyzed product of agar was characterized as neoagarobiose. Furthermore, this work is the first evidence of cold-adapted agarase in Antarctic psychrophilic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine, food and cosmetic industries.
authors.affiliation: Key Laboratory of Marine Bioactive Substances, The First Institute of Oceanography, Qingdao, China .
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Chemical Engineering, Qingdao University of Science & Technology, Qingdao, China .
authors.forename: Qiushi
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Marine Science and Engineering College, Qingdao Agriculture University, Qingdao, China .
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Marine Science and Engineering College, Qingdao Agriculture University, Qingdao, China .
authors.forename: Yuan
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology*; D000362:Agar / Q000378:metabolism*; D000864:Antarctic Regions; D001426:Bacterial Proteins / Q000378:metabolism; D003080:Cold Temperature; D004187:Disaccharides / Q000096:biosynthesis; D019015:Geologic Sediments / Q000382:microbiology; D006026:Glycoside Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D006868:Hydrolysis; D031161:Pseudoalteromonas / Q000201:enzymology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004187:Disaccharides; D012336:RNA, Ribosomal, 16S; C068544:neoagarobiose; D000362:Agar; D006026:Glycoside Hydrolases; C019624:agarase
keywords: characterization; cold-adapted agarase; psychrophilic bacteria; purification