Purification and Characterization of Alginate Lyase from Marine Bacterium, Pseudoalteromonas sp. KY3

Abstract

Marine bacterium showing the alginate degrading activity was isolated from Kwangyang Bay and designated as Pseudoalteromonas sp. KY3. This strain was identified as a genus Pseudoalteromonas to by the results from morphological and biochemical studies and on the basis of the analysis of 16S rRNA gene sequence. The optimum culture conditions for growth of the Pseudoalteromonas sp. KY3 were at 30℃, PPES-II (pH 8.0, 2% NaCl) and gentle shaking (180 rpm). Pseudoalteromonas sp. KY3 produced an extracellular enzyme showing alginate lyase activity. This enzyme was purified by sequential purification steps including chromatographic techniques and turned out to be approximately 45 KDa of molecular weight analysed by SDS-PAGE. Purified enzyme showed stability at the pH range of 7.5-8.5. Purified enzyme showed the most activity at the pH range of 7.0-8.5. The enzyme also showed the most stability at 0℃ and the most activity at 30℃. Enzymatic activity was inhibited by HgCl₂, PbCl₂ and EDTA while it was stimulated by CaCl₂ and 2-mercaptoethanol, respectively. The Km value of alginate lyase estimated on 697.3㎍.