Variant
Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.
1. An isolated polypeptide having cellobiohydrolase I activity, wherein said polypeptide has a sequence homology of at least 90% with SEQ ID NO: 10 having a substitution at Q101.
2. The polypeptide of claim 1 wherein said substitution is Q101Y or Q101H.
3. The polypeptide of claim 1 further comprising a signal sequence.
4. The polypeptide of claim 1 , wherein said polypeptide is SEQ ID NO:10 with a single substitution at Q101.
5. A recombinant cell culture composition, comprising the polypeptide of claim 1 .
6. The cell culture composition of claim 5 , wherein, said substitution is Q101Y or Q101H.
7. The polypeptide of claim 5 further comprising a signal sequence.
8. The cell culture composition of claim 5 , wherein said cells in said culture are filamentous fungus cells.
9. The cell culture composition of claim 8 , wherein said filamentous fungus cells are selected from the group consisting of Trichoderma, Penicillium, Humicola, Aspergillus, Chrysosporium, Fusarium, Hypocrea, and Emericella,
10. The cell culture composition of claim 5 , wherein said polypeptide is SEQ ID NO:10 with a single substitution at Q101.
11. A method of converting biomass to sugars comprising contacting the biomass with the polypeptide of claim 1 having cellobiohydrolase I activity wherein said polypeptide has enhanced activity relative to T. reesei in either a PCS conversion assay 65° C. or a PASC assay at 38° C.
12. A method of converting biomass to sugars comprising contacting said biomass with a polypeptide having cellobiohydrolase I activity according to claim 1 .