A Method for Depolymerization of Alginate Using the Enzyme System of Flavobacterium multivolum.

Abstract

We investigated a method for depolymerization of alginate with the enzyme system of Flavobacterium multivolum. The enzyme exhibited the maximum activity at pH 7.0 and 50°C, and was stable in the pH range of 4 to 8 and at temperature up to 40°C. Enzyme activity was activated in the presence of around 0.1M of NaCl, KCl and MgCl2 in reaction mixture. The enzyme decreased the viscosities of solutions of sodium, potassium and ammonium alginates, and solution of propylene glycol ester of alginate. The enzyme belonged to alginate lyase and degraded Na-alginate by an endo-wise manner. The time-course of change in viscosity on large scale reaction is almost the same as that of beaker scale reaction, and the clarification of alginate digest was possible by the treatment with active carbon. Actually, a 4.9kg of Na-alginate (M/G=1.04) was degraded with the enzyme system (32.3g of the enzyme powder with 31814 U) of F. multivolum at pH 6.8 and 45°C for 2.5 h. The viscosity of reaction mixture, thus obtained, was about 4 centipoises (3.5%, W/W).