Production method for preparing high-purity oligosaccharides by hemicellulose enzymolysis

The invention provides a method for preparing high-purity oligosaccharides by the enzymolysis of hemicellulose containing mannosan, and a product which is a high-effect beta-mannase BM-II produced by fermenting bacillus subtilis TQBm with the preservation No. of CCTCC No: M 211147. Konjac glucomannan, guar gum, sophora bean gum, sesbania gum and other hemicelluloses containing the mannosan are hydrolyzed into relatively small molecule materials, and then are desalted, decolored and deodorized through centrifugal separation, flocculation clarification and ion exchange techniques, large molecule materials in sugar solution are separated by the combination of an ultrafiltration technique and a molecular sieve chromatography technique, and finally the high-purity oligosaccharides is prepared through concentration and drying. The method for preparing the high-purity oligosaccharides disclosed by the invention has the advantages of simple operation, good separation effect, low cost and no chemical pollution, and industrialized production can be realized. The oligosaccharides product disclosed by the invention can obviously proliferate bifidobacteria in the human intestinal tract and otherbeneficial bacteria and obviously reduce enterobacter and other harmful bacteria, has the functions of blood sugar and blood fat reduction and immunoregulation, and is a novel raw material and assistant for gastrointestinal health, blood sugar and fat reducing, immunoregulation and disease resisting and preventing medicines.