Abstract: A glucanase having increased enzyme activity and thermostability is disclosed. The glucanase comprises a modified amino acid sequence of SEQ ID NO: 2, wherein valine at position 18 is substituted with tyrosine and tryptophan at position 203 is substituted with tyrosine.

Abstract: A thermostable cellulase having increased enzyme activity is disclosed. The cellulase comprises a modified amino acid sequence of SEQ ID NO: 2, wherein the tyrosine at position 61 is substituted with an amino acid selected from the group consisting of phenylalanine, alanine and glycine.

Abstract: A xylanase gene, denoted xynR8, encoding a xylanase (XynR8) obtained from the unisolated rumen microorganisms is provided. The DNA sequence of the xynR8 gene, xylanase, is also provided, the enzyme is thermostable, and highly specific for xylans with high activity. Transformation of microbial hosts with the xynR8 gene is described. A method for degrading the xylan-containing structure comprises hydrolyzing the ?-1,4-glycosidic bonds of xylans by contacting xylanase is provided, and a composition employing the above-mentioned hydrolyzing method is further addressed.

Abstract: A xylanase gene, denoted xynR8, encoding a novel xylanase (XynR8) obtained from the unisolated rumen microorganisms is provided. The DNA sequence of the xynR8 gene, xylanase, is also provided, the enzyme is thermo-tolerable, and highly specific for xylans with high activity. Transformation of microbial hosts with the xynR8 gene is described. A method for degrading the xylan-containing structure comprises hydrolyzing the ?-1,4-glycosidic bonds of xylans by contacting xylanase is provided, and a composition employing the above-mentioned hydrolyzing method is further addressed.