TECHNOLOGY FOCUS - BIOTECHNOLOGY - Isolation (Claimed): The isolated polypeptide, preferably GH45 or Grp 2/3 domain is separated from expansin protein, expansin-like protein or bacterial protein. The expansin protein or expansin-like protein is chosen from alpha -expansin (EXPA), beta -expansin (EXPB), expansin-like A (EXLA), expansin-like B (EXLB), expansin-like group X (EXLX), Bacillus subtilis (Bs)EXLX, Hahella chejuensis (Hc)EXLX2, and Stigmatella aurantiaca (Sa)EXLX. The bacterial protein is isolated from a bacterium chosen from Leptothrix cholodnii Lch, Clavibacter michiganensis Cmi, Nakamurella multipartita Nmu, Frankia sp. Fsp, Micromonospora sp., Msp, Streptomyces sviceus Ssv, Catenulispora acidiphila Cac, Plesiocystis pacifica Ppa, Herpetosiphon aurantiacus Hau, Chloroflexus aurantiacus Cau, Acidovorax avenae Aav, Roseiflexus sp. Rsp, Myxococcus xanthus Mxa, Stigmatella aurantiaca Sau, Xanthomonas campestris Xca, Ralstonia solanacearum Rso, Xylella fastidiosa Xfa, Pectobacterium atrosepticum Pat, and Dickeya zeae Dze. Preferred Protein: The polysaccharide hydrolase is chosen from cellulase, hemicellulase, alpha -amylase, glucoamylase, pectinase, xylanase, cellobiase, and their combination. The amount of isolated polypeptide for degrading the polysaccharide is 1-1000 nmole/g. The concentration of polysaccharide hydrolase added to the material is 2-60 filter paper unit (FPU)/g of the polysaccharide. Preferred Polysaccharide: The polysaccharide is chosen from cellulose, hemicellulose, glucose, xylose, pectin, xylan, and their combination. The polysaccharide material is obtained from a cellulosic or lignocellulosic biomass. The polysaccharide material is obtained from a cellulosic or lignocellulosic biomass. Preferred Sequence: The GH45 domain exhibits at least 70% sequence homology with a cDNA comprising a 333 base pair sequence (SEQ ID NO: 4) fully defined in the specification. The Grp 2/3 domain exhibits at least 70% sequence homology with a cDNA comprising a 291 base pair sequence (SEQ ID NO: 5) fully defined in the specification. Preferred Method: The method (M1) further involves pretreating the cellulosic or lignocellulosic biomass with heat, acidic material, basic material, or their combination. The method (M1) further involves washing the polysaccharide material after the isolated polypeptide added to the material, and incubating the material with polysaccharide hydrolase, hydrolysis catalyst, acid, microorganism, or their combination to obtain monosaccharides. The method (M1) further involves fermenting monosaccharides obtained from the polysaccharide material with a microorganism to obtain a biofuel. EXAMPLE - No suitable example given.