玉米芯木聚糖的碱法提取及其酶解产物研究

为了探明碱法提取玉米芯木聚糖的最适条件,对玉米芯木聚糖的提取条件进行了研究,并对提取的不同木聚糖进行酶解。结果表明:碱法提取玉米芯木聚糖时,在100g/L NaOH、1∶20固液比、60℃、3h的条件下进行一次性提取,木聚糖得率达29.45%。提取液离心可得到纯度达80.5%的水不溶性木聚糖(wis-X),乙醇沉淀得到的水溶性木聚糖(ws-X)纯度为6.4%。wis-X的酶解产物是木糖和3种低聚木糖,ws-X的酶解产物是葡萄糖和3种低聚木糖。因此,玉米芯是制备wis-X和低聚木糖的理想原料,从简化工艺和节约成本角度考虑,碱提前不需稀酸预处理,适宜条件下提取1次即可。

Xylan Extraction from Corncob by Alkaline Method and Study on Its Enzymatic Hydrolysates

The alkaline method was used to extract xylan from corncob.The influence on xylan yield of some factors such as alkaline concentration,the ratio of solid to liquid,extraction time,extraction temperature,whether carrying on pretreatment,and the times of extraction was analyzed.Besides,the different ingredients of xylan extracted from corncob were hydrolyzed by xylanase.The results showed that one-time extraction under the conditions of 100 g/L NaOH,60 ℃ and 3 hours with the ratio of solid to liquid of 1∶20,the xylan yield reached 29.45%.To centrifugalize the extraction solution could get water-insoluble xylan(wis-X) with the purity of 80.5%.The water-soluble xylan(ws-X) obtained by alcohol precipitation had the purity of 6.4%.Hydrolyzed by xylanase,wis-X generated xylose and three kinds of xylooligosaccharides(XOS).The enzymatic hydrolysates of ws-X were glucose and three kinds of XOS.Therefore,corncob is an ideal resource to produce wis-X and XOS.In consideration of the cost and simplifying processions,pretreatment with dilute acid and extraction more than one time are unnecessary.