Xos The Chromatographic Separation Of Each Component And The Proliferation Of Bifidobacteria

Xylan enzymatic hydrolysate residues, agriculture castoffs, were taken as original materials in the experiments. There were three topics discussed in the dissertation, which were the degrading of xylan enzymatic hydrolysate residues at a higher temperature, the separation of the xylooligosaccharides by chromatography and the proliferation, use rules to xylo-oligosaccharides and metabolizing mechanism of Bifidobacterium odolescentis, etc. The research showed that xylan enzymatic hydrolysate residues could be degraded into xylo-oligosaccharides at 180℃,furthermore the longer the reaction time, the deeper the degraded degree. Three main parameters would be changed while this happened, for example the DP( averge degree of polymerization) decreased from 3.37 to 1.54 , pH decreased from 5.2 to 4.5 and the xylan content increased from 0.45g to 0.91g in the filtrate simultaneously. By using the 3.0×120cm column and taking Bio-Gel P-4 as the media, the degraded productions of the xylan enzymatic hydrolysate residues could be effectively separated by chromatography. It was showed that better separation results would be reached if the following conditions was met, for instance, sample volume at 7ml, flow rate 0.4ml per minute, column temperature at 28℃, de-air distilled water elution. Isolated xylooligosaccharide fractions were collected. Based on the experiment mentioned above, if the 1.6×100cm column and the media of Bio-Gel P-2 were chosen, with the aid of FPLC system, the deeper separation of the xylooligosaccharides would be met. The best process conditions for this deeper separation was the following, for example, sample volume at 1ml, flow rate at 0.05ml per minute, column temperature at 48℃, de-air distilled water elution. By means of rechromatography, purer single element from xylobiose to xylooctaose would be got finally. The anaerobic experiment of Bifidobacterium odolescentis indicated when the culture media of xylobiose, xylotriose and xyloterose, the culture media of xyloterose, xylopentaose and xylohexaose, and the culture media of xylohexaose, xyloheptaose and xylooctaose were in use separately, the proliferation multiple of the Bifidobacterium odolescentis were 5.4, 3.0 and 2.0 correspondingly. The results showed that xylobiose, xylotriose, xyloterose, xylopentaose were all good bifidum factors and xylohexaose, xyloheptaose, xylooctaose could also proliferate the Bifidobacterium odolescentis at some degrees. the Bifidobacterium odolescentis could utilize the self-decomposed enzymes to degrade xylo-oligosaccharides effectively. While the Bifidobacterium odolescentis made first use of both xylotriose and xyloterose, they sent out a kind of enzymes that could degrade higher DP xylo-oligosaccharides. The metabolism productions of Bifidobacterium odolescentis in the xylo-oligosaccharides were short-chain fatty acids(SCFA), such as lactic, acetic, propionic ,butyric acids, and the content of total acid was from 2.28g/L to 5.73g/L. The Bifidobacterium odolescentis which were cultured appeared some shapes, for example, straight stick, curved stick or branch. The results of this dissertation provide a new way to prepare single element of xylo-oligosaccharides and make a matting for the deeper reseach of the Bifidobacterium odolescentis proliferation and metabolizing mechanism.