원문정보
초록
영어
A xylanolytic bacterium, Cellulosimicrobium sp. HY-13, was isolated from the digestive tract of an earthworm, Eisenia fetida. The purified endo-β-1,4-xylanase (XylK) from strain HY-13 was an unique enzyme with the N-terminal amino acid sequence of APSTLEAAAE and a relative molecular mass of 36 kDa. It was most active at pH 6.0 and 55oC. The Vmax and Km values of XylK toward oat spelt xylan were determined to be 4,067 IU/mg and 2.78 mg/ml, respectively. The enzyme primarily degraded a xylan to a series of xylooligosaccharides of xylobiose to xylotetraose, but it could not further hydrolyze xylobiose to xylose. The present results suggest that the relatively highly active XylK lacking exo-xylanolytic activity is a promising candidate for the efficient production of non-digestible xylooligosaccharides that may have beneficial effects to gastrointestinal health by promoting the growth of probiotics.