Enzymic Production Of Xylooligosaccharides From Corncob In A Pilot Scale

Xylooligosaccharides, as a sort of functional oligosaccharides, can promote the proliferation of Bifldobacterium in the intestinum crassum. This paper is mainly concerned with the study on the enzymic production of xylooligosaccharides in a pilot scale which includes the research of production conditions and the optimization of process.The effect of temperature and time on the extraction of xylan by autoclaving was investigated. Xylan was extracted from corncob in the condition of 160℃ and 1.5 hours after corncob was treated with 0.1%H2SO4 at 60℃. Xylanase was obtained with Asperillus niger solid state fermentation at 28 ℃ for 72 hours. The xylanase activity was no less than 2500IU/g dry medium. The influence of periodic air pressure oscillation on xylanase activity was also studied. The result showed that the oscillation could improve the xylanase activity. The conditions of xylan hydrolysis into xylooligosaccharides by xylanase were as follows: pH 5.5, temperature 50℃, reaction time 3.5 hours, the amount of xylanase more than 10IU/g corncob. The separation and purification of xylooligosaccharides has been improved. Macroporous ion exchange resins D72 and D202 were used to separate pectin, desalt and decolor. The syrup of xylooligosaccharides was obtained with active carbon decolorizing further and concerntration in which xylooligosaccharides were about 70% among the total sugar.The monosaccharedes separation from xylooligosaccharides was alsostudied. The syrup was completely isolated into monosaccharides and oligosaccharides by successive displacement with water and 60% ethanol from a charcoal column. Charcoal columns also have a large separation capacity for sugar.