Patent ID: 7947656

Claim:
A process of producing cellooligosaccharide, comprising enzymatically decomposing, in the presence of cellulase, a water-insoluble natural cellulosic material having an average degree of polymerization not greater than 700, an average particle size not greater than 100 μm, and a diethyl ether-soluble substance content of less than 1% by mass, the water-insoluble natural cellulosic material containing 10% or more by mass of a colloidal cellulose component, wherein the cellulase has an activity ratio of 0.5 or less, the activity ratio being a ratio of β-glucosidase activity to crystalline cellulose-decomposing activity at a temperature of 40° C., and the cellulase is obtained by culturing a cellulase-producing fungi at a pH of less than 3.5, the cellulase-producing fungi belonging to the Trichoderma reesei NBRC31329 strain and the Trichoderma reesei GL-1 strain.