β-Mannanase and Xylanase of Bacillus subtilis 5H Active for Bleaching of Crude Pulp

概要

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A bacterial strain, 5H was isolated as a utilizer of locust bean gum (LBG) from soil in Chiang Mai, Thailand, and identified as Bacillus subtilis. Strain 5H produced β-mannanase and xylanase, which were purified to homogeneity from the culture filtrate by ion exchange chromatography and gel filtration. The molecular weights of β-mannanase and xylanase were found to be 37, 000 and 26, 000 by sodium dodecyl sulfonate polyacrylamide gel electrophoresis, respectively. The enzymatic properties of both were determined. Mannanase hydrolyzed LBG and konjak mannan endwisely, to a final hydrolytic degree of 15% and 21%, respectively, and the main products of both were disaccharides. Xylanase hydrolyzed larch wood xylan and oat spelt xylan, to a final hydrolytic degree of 19% and 38%, respectively, and produced mainly disaccharides. This culture filtrate (4.9 units/ml β-mannanase and 3.2 units/ml xylanase), a mixture of purified β-mannanase (4.9 units/ml) and xylanase (3.2 units/ml), and purified xylanase (3.2 units/ml) bleached crude paper pulp from 30% to 38% brightness, and xylanase was found to be more effective for paper-bleaching than β-mannanase.
社団法人日本生物工学会の論文
1998-11-25