Abstract: It was comparatively investigated that xylan was hydrolyzed by crude and purified xylanases in ultrafiltration membrane reactor (UMR) and conventional stirring batch reactor (CSBR). After enzymatic hydrolysis of 525 min in UMR using crude or purified xylanases,the obtained individual oligosaccharide components (xylobiose, xylotriose, xylotetraose, and xylopentaose) in the hydrolysates accounted for some 20% respectively, and xylose about 9.5%. The xylo-oligosaccharide yields, the ratio of xylo-oligosaccharides to total saccharides, and the productivity of xylo-oligosaccharides in UMR using crude xylanases were 18.7%,14.9% and 16.0% higher than those in CSBR using purified xylanases, respectively, but xylose yield was 55.5% lower than that in the latter case. The amount of individual oligosaccharide component in UMR was almost equal in the UF membrane reactor using crude xylanases, and more xylobiose was obtained in the CSBR using purified xylanases. Therefore,high-quality xylo-oligosaccharides could be prepared using crude xylanase in UMR.

Key words: xylanases, xylo-oligosaccharides, ultrafiltraion membrane reactor