Purification and characterization of cold-adapted beta-agarase from an Antarctic psychrophilic strain

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 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.

The Screening and Study of Arctic Marine Psychrophilic Bacterial for Anti-tumor and Antibacterial Activity / 微生物学通报

In this study, 101 strains of bacteria were isolated from arct ic water and sediment samples. The methanol extracts of the fermented broth prod uced by these strains were screened in vitro for anti-tumor activity on mou se tsFT210 cells using the method of flow cytometry, and screened for antibacter ial activity by the method of paper disk diffusion. The result showed that one strain exhibited anti-tumor activity and eight strains had antibacterial activ ity. The stability of the antibacterial components produced by strain AR084 an d its optimum medium were also studied. The research indicated that arctic bac teria had potential application in pharmaceutics.