Abstract
A novel mannanase that has a strict specificity for the α-1, 3-mannosidic linkage has been isolated and characterized. The enzyme was purified to homogeneity from the cultural supernatant of a soil bacterium, Flavobacterium sp. AS-9 isolated by enrichment culture on Auricularia mannan of which the structure was an α-1, 3-linked D-mannan main chain branched with short segments of xylose or glucuronic acid. Purified mannanase was optimally active between pH 6 and 8. The apparent molecular mass of the enzyme was 94 kDa by SDS gel electrophoresis under reducing conditions and 100 kDa by gel filtration HPLC. The enzyme only hydrolyzed α-1, 3-D-mannan with endo-type action to produce α-1, 3-mannooligosaccharides of various sizes. The smallest product was α-1, 3-mannobiose.
