Abstract: Ultrafiltration is a necessary process to ensure an efficient operation of the ion-exchange column chromatography of xyolitol fermentation broth of the hemicellulose hydrolysate of sugar cane bagasse. After desalination by ion-exchange column process, followed by decoloration with active carbon, the purified xylitol syrup was concentrated up to soluble solids 80%. Then, the xylitol product could be crystallized out with purity up to 98.5%. The xylitol preparation of the second and third crystallization of the mother liquor could not gain a purity of 98.5% unless it has been recrystallized. In this process, the ultimate yield of xylitol product with a purity of 98.5% could reach about 70.6%. Under this technics, the suitable cut-molecular weight of ultrafiltration membrane is 5000kD and the proper value ratio of anion resin to cation resin is about 1.5:1, while the reasonable dosage of active carbon equals to 2.5 percent of the amount of soluble solids in syrup. In the crystallized mother liquor, if the concentration of arabinose is 45.0% higher than that of xylitol, or the concentration of xylose is 12.6% higher than that of xylitol, this two will crystallize out at same time as the xylitol crystallizs. It is difficult to efficiently purify the xylitol from such mother liquor only by the crystallization process alone.

Key words: sugar cane bagasse, hemicellulose hydrolysate, fermentation, xylitol, purificating column chromatography