Enzyme preparations with recombinantly-altered cellulose profiles and methods for their production
First Claim
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1. A method for producing an enzyme preparation in a culture medium, said method comprising the steps of:
- (a) modifying a Trichoderma host cell such that said host cell is partially or completely deficient in expressing one or more endogenous cellulase enzymes;
(b) transforming the host cell of part (a) with a genetic construct comprising a nucleotide sequence encoding a protein selected from the group consisting of a hemicellulase, a pectin degrading enzyme, a lignin degrading enzyme other than lignin peroxidase LIII of P. radiata, and a cellulolytic enzyme, wherein the transformation inserts said nucleotide sequence into the chromosome of said host cell;
(c) screening said host cell of part (b) and identifying a host cell which expresses said protein;
(d) cultivating said transformed Trichoderma host cell of part (c) under conditions which allow the expression of said protein; and
(e) recovering the culture medium from the cultivation of part (d), wherein said culture medium contains said protein and the enzymes secreted by said transformed Trichoderma host cell during the cultivation of part (d).
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Abstract
Enzyme preparations enriched in hemicellulase-, pectin-, and/or lignin-degrading enzymes are described which are also partially or completely deficient in cellulase degrading activity. Such preparations may be utilized in an crude, unpurified form and are especially useful in the production of pulp and paper.
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31 Claims
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1. A method for producing an enzyme preparation in a culture medium, said method comprising the steps of:
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(a) modifying a Trichoderma host cell such that said host cell is partially or completely deficient in expressing one or more endogenous cellulase enzymes; (b) transforming the host cell of part (a) with a genetic construct comprising a nucleotide sequence encoding a protein selected from the group consisting of a hemicellulase, a pectin degrading enzyme, a lignin degrading enzyme other than lignin peroxidase LIII of P. radiata, and a cellulolytic enzyme, wherein the transformation inserts said nucleotide sequence into the chromosome of said host cell; (c) screening said host cell of part (b) and identifying a host cell which expresses said protein; (d) cultivating said transformed Trichoderma host cell of part (c) under conditions which allow the expression of said protein; and (e) recovering the culture medium from the cultivation of part (d), wherein said culture medium contains said protein and the enzymes secreted by said transformed Trichoderma host cell during the cultivation of part (d). - View Dependent Claims (2, 3, 4, 5, 6, 8, 9)
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- 7. A transformed Trichoderma host cell, wherein said transformed Trichoderma host cell is modified such that said host cell is partially or completely deficient in expressing one or more endogenous cellulase enzymes and wherein said transformed Trichoderma host cell has been transformed with a genetic construct comprising a nucleotide sequence encoding a protein selected from the group consisting of a hemicellulase, a pectin degrading enzyme, a lignin degrading enzyme other than lignin peroxidase LIII of P. radiata, and a cellulolytic enzyme, and wherein said nucleotide sequence encoding said protein has been integrated into the genome of said transformed Trichoderma host cell.
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13. A method for producing an enzyme preparation deficient in an endogenous Trichoderma cellulase in a culture medium, said method comprising the steps of:
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(a) transforming a Trichoderma host cell, wherein said transformation results in a host cell that is partially or completely deficient in expressing one or more endogenous cellulase enzymes; (b) cultivating said transformed Trichoderma host cell; (c) recovering the culture medium after said cultivation of part (b), said culture medium containing the enzymes secreted by said Trichoderma host cell during said cultivation; and (d) preparing said enzyme preparation from the culture medium recovered in part (c).
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- 14. A transformed Trichoderma host cell, wherein said transformed Trichoderma host cell is modified such that said host cell is partially or completely deficient in expressing one or more endogenous cellulase enzymes and wherein said transformed Trichoderma host cell is capable of expressing one or more endogenous enzymes selected from the group consisting of a hemicellulase, a pectin degrading enzyme, and a cellulolytic enzyme.
Specification