Partial purification and characterization of a 1,3-β-d-glucanase fromGanoderma tsugae

Abstract

The crude broth from a submerged culture ofGanoderma tsugae was assayed for activity against laminarin, and enzyme staining indicated the presence of 1,3-β-d-glucanases. 1,3-β-d-glucanase activity increased rapidly after the stationary growth phase ofGanoderma tsugae. At the same time the glucose was almost depleted and the amount of extracellular polysaccharide decreased in the broth medium. There were two 1,3-β-d-glucanase isozymes in the culture broth ofGanoderma tsugae. After gel filtration, the first peak showed a high activity for laminarin; it was designated as 1,3-β-d-glucanase (I). The second peak exhibited much less activity; it was designated as 1,3-β-d-glucanase (II). Since 1,3-β-d-glucanase (II) activity was very low, and there were probably some inhibitors present in the 1,3-β-d-glucanase (II) fractions, we collected only the fractions that contained 1,3-β-d-glucanase (I) activity. 1,3-β-d-glucanase (I) was specific for laminarin and was found to hydrolyze extracellular polysaccharide in the culture broth ofGanoderma tsugae. The maximum activity of 1,3-β-d-glucanase (I) was at about 50 °C and pH 5.0. The enzyme was stable at pH 5.0 and at temperatures below 40 °C.