The activity of β-1,3-glucanase from Trichoderma harzianum in native form and after immobilization on calcium alginate

Abstract

β-1,3-Glucanase from Trichoderma harzianum was successfully immobilized in calcium alginate. Immobilized enzyme in calcium alginate exhibited 51% and 34% immobilization efficiency for pure and crude enzyme preparations, respectively, and could be reused seven times without severe loss in enzyme activity. The retained activity after five successive reuses was 50%. Some properties of free and immobilized β-1,3-glucanase preparations were investigated. Enzyme preparations showed relatively high activities in acidic pH range. The activity peak of immobilized enzyme was relatively wider (pH 3 – 8) than the free enzyme (pH 3 – 6). The pH-stability profiles of the two enzyme preparations were stable at pH 5, and the activity of immobilized enzyme showed higher pH stability (half-life) than the free enzyme at pH 3 and 9. The temperature optimum of β-1,3-glucanase preparations (free or immobilized) was in the range from 50 – 60°C. Immobilized β-1,3-glucanase showed a slightly higher thermal stability (half-life) than the free enzyme. The activity of free enzyme was strongly inhibited by Hg2+ and Hg+, whereas, the inhibition effect was partially on the alginate encapsulated enzyme. Free samples of pure β-1,3-glucanase showed a t 1/2 of approximately 60 days when stored in acetate buffer (50 mM, pH 4.8), at temperatures around 20 and 30°C, however, the resultant beads of pure enzyme showed significantly high storage stability when examined under the same conditions. Preparations of free and immobilized β-1,3-glucanase inhibited the growth of Fusarium oxysporum and Pythium ultimum.