Rational Screening Of Isomaltooligosaccharide Excellent Strains And The Research Of Efficient Conversion Technology

The traditional process of producing isomaltooligosaccharide is used starch as raw materials,conversion with a-glucosidase.But China’s a-glucosidase basic all imported from Japan.In order to break the monopoly in this area,this article use Aspergillus niger strain K7 as the original strain,which was preserved in my laboratory,to produce a-glucosidase.According to its enzyme production characteristics,design targeted screening model.Screened a excellent production isomaltooligosaccharide strain F86.This strains glucoamylase activity is relatively low,a-glucosidase activity is relatively high,and the one step fermentation time is 8 h less than the K7.The glucose content has remained at a low level untill the fermentation is over with F86 one step fermentation.And the glucose content is only 14.7%,and reduced 15%compare with K7,low glucose content ensure the quality of the product.At the same time,temperature、pH tolerated better than K7,can stable at the conversion environment:42℃ and pH4.2.By optimizing the conditions for a-glucosidase enzyme production,expand the fermentation scale and study the reuse of the mycelium,and established the process of carrier-free F86 cells reuse,the time of single producing is 7 h.With the same conversion time,F86 conversion of cassava starch was two times of K7.Repeated batch up to 30 batches,largely reduced the cost of producting of isomaltooligosaccharide.The products composition:its glucose content is 15%and 20%less than the IMO-50;effective isomaltooligosaccharide is 55%,it is 20%more than the IMO-50.This level is belonged of the high quality isomaltooligosaccharide poduct.