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 agardegrading 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 Mg2+,Mn2+,K+;Ca2+,Na+,Ba2+,Zn2+,Cu2+, Co2+,Fe2+,Sr2+ 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.