Process Research On Hydrolysis Production Of Xylooligosaccharides From Hemicellulose Of Reed

For exploring the recycling use of reeds,the process for producing xylooligosaccharides with hydrolysis of reed material was conceived and tested.The research work included the process for extracting xylan from reed material,the process for enzymatic hydrolysis of steam exploded reed,the process for decoloring of the xylooligosaccharides hydrolysate and the research of using column chromatography to separate and purificate xylooligosaccharides hydrolysate.The research on the pretreamment of reed show that alkalic cooking,acid cooking and steam explosion all can extract xylan from reed.Also,steam explosion can get a little xylooligosaccharides.The xylooligosaccharides’ quantity which came from steam explosion increases with pressure.At the same pressure,alkalic steam explosion could got more xylans.Under the same enzymatic hydrolysis condition,pressure under 1.40Mpa with alkali acquired better enzymatic hydrolysis effect and this method is the most suitable for using enzymatic hydrolysis to produce xylooligosaccharides.The research on the xylanase hydrolysis of steam exploded reed showed that at 1:10 of ratio of reed material to deionized water,5%(based on dried reed) of xylanase addition,pH4.8,45℃ of enzymatic hydrolysis and 24h of reaction time could obtain the best enzymatic hydrolysis effect.In the hydrolysate,the amount of soluble total sugar and reducing sugar was 6.39mg/ml and 3.51mg/ml,The amount of xylooligosaccharides was 14.00%(based on dried reed) in the hydrolysate analyzed by HPLC.And the main ingredients were xylobiose and xylotriose,which occupied 12.29% and 1.71% (based on dried reed).Under the best enzymatic hydrolysis conditions,the xylobiose content got maximum at 24h,and the xylotriose content got maximum at 18h.Different decoloring measures for xylooligosaccharide solution were stuied.Results showed that acid flocculation possessed certain decolorzation effect.In the conditions of pH3.0 and 50℃,the decolorzation rate was 45.79% after 30min.The powder carbon which modified by ammonia possessed a better decolorizing effect.Under optimizing conditions of pH3, temperature70℃,30% of powder activated carbon(based on dried solids),170r/min,70min of decolorization time,the decolorzation rate was 90.31%.Acid flocculation with activated carbon to decolor xylooligosaccharide solution that the decolorzation rate was 88.60% with addition 20% of activated carbon(based on dried solids).Finally,using granular activated carbon chromatography method to separate and purificate the decolored xylooligosaccharide solution, and choosing 30% of alcohol as eluant.Then getting the xylooligosaccharide product which included xylobiose and xylotriose through concentration.The extraction efficiency of xylooligosaccharides was 62.9%.