木聚糖酶解反应与膜分离技术研究

STUDY ON ENZYMATIC HYDROLYSIS OF XYLAN AND ITS MEMBRANE SEPARATION TECHNOLOGY

过程耦合是应用技术领域研究的热点之一 ,膜及膜分离技术的开发促进了过程耦合技术的发展。如膜超滤、膜萃取、膜蒸馏、渗透蒸发。在超滤膜反应器中木聚糖酶解制备低聚木糖的条件 :酶体积用量1 0 % ,木聚糖质量浓度 3 0 .0 g/L ,稀释率 1h-1,pH值 5 .0 ,反应温度 48℃ ,酶解时间 1 3 5min。在该条件下 ,低聚木糖得率、木糖得率、低聚木糖生产能力及低聚木糖与总糖之比分别为 2 8.5 % ,4.1 % ,3 .80g/ (L·h)和0 .87,并比较了分批加料、浓缩酶、常规反应器中酶解反应效果 ,浓缩木聚糖酶酶解结果表明 :木糖得率很低(0 .2 % ) ,低聚木糖得率为 3 5 .9%。

Processes coupling is one of the hotspots in applied technology.The development of processes coupling has been promoted by membrane separation technology,such as membrane ultrafiltration,membrane extraction,membrane distillation,pervaporation and affinity membrane.Preparation of xylo oligosaccharides from xylan by enzymatic hydrolysis in membrane ultrafiltration reactor was carried out under following conditions:enzyme dosage 10%(volum ratio),xylan concentration 30.0 g/L,dilution rate 1 h -1 ,pH 5.0,reaction temperature 48 ℃,enzymatic hydrolysis time 135 min.Under these conditions,xylo oligosaccharides yield,xylose yield,productivity of xylo oligosaccharides and the ratio of xylo oligosaccharides to total sugar was 28.5%,4.1%, 3.80 g/(L·h) and 0.87,respectively.Comparison of the results on enzymatic hydrolysis by batch feed,purified xylanases,in the conventional reactor was conducted.Results showed that yield of xylose,in the products of hydrolysis by xylanase treatment was kept at a rather low level(0.2%) and oligosaccharide yield was 35.9%.Addition of precipitant H was effective to remove β xylosidase from xylanase system.This technique would provide a new way for oligosaccharide production.