Fungal strains

• US 9,068,235 B2
• Filed: 11/01/2011
• Issued: 06/30/2015
• Est. Priority Date: 11/02/2010
• Status: Active Grant

• Current Assignee: Codexis, Inc.
• Original Assignee: Codexis, Inc.
• Inventors: Baidyaroy, Dipnath, Dhawan, Ish Kumar
• Primary Examiner(s): PAK, YONG D
• Application Number:
  US13/286,860
• Publication Number:
  US 20120107880A1
• Time in Patent Office: 1,337 Days
• US Class Current: 1/1
• CPC Class Codes: C12N 9/0006 acting on CH-OH groups as donors (1.1)
• CPC Class Codes: C12N 9/2437 Cellulases (3.2.1.4; 3.2.1.74; 3.2.1.91; 3.2.1.150)
• CPC Class Codes: C12N 9/2445 Beta-glucosidase (3.2.1.21)
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 19/12 Disaccharides
• CPC Class Codes: C12P 19/14 produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase , e.g. by cellulase, hemicellulase
• CPC Class Codes: C12P 2203/00 Fermentation products obtained from optionally pretreated or hydrolyzed cellulosic or lignocellulosic material as the carbon source ethanol C12P7/10
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C12Y 101/99018 Cellobiose oxidase (1.1.99.18)
• CPC Class Codes: C12Y 302/01021 Beta-glucosidase (3.2.1.21)
• CPC Class Codes: C13K 1/02 obtained by saccharification of cellulosic materials manufacture of fodder A23K10/32
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

The present invention provides improved fungal strains. In some embodiments, the improved fungal strains find use in hydrolyzing cellulosic material to glucose.

Claims

1. A Myceliophthora thermophila fungal cell that has been genetically modified to reduce the amount of endogenous cellobiose dehydrogenase I activity that is secreted by the cell, wherein said cell comprises a deletion in the cellobiose dehydrogenase 1 (cdh1) gene set forth in SEQ ID NO:

1.

2. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to disrupt the secretion signal peptide of the cellobiose dehydrogenase I.

3. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to reduce the amount of the endogenous cellobiose dehydrogenase I expressed by the cell.

4. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to disrupt a translation initiation sequence in the transcript encoding the endogenous cellobiose dehydrogenase I.

5. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to introduce a frameshift mutation in the transcript encoding the endogenous cellobiose dehydrogenase I.

6. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to reduce the transcription level of a gene encoding the endogenous cellobiose dehydrogenase I.

7. The Myceliophthora thermophila fungal cell of claim 6, wherein said fungal cell has been genetically modified to disrupt the promoter of a gene encoding endogenous cellobiose dehydrogenase I.

8. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to at least partially delete a gene encoding endogenous cellobiose dehydrogenase I.

9. The Myceliophthora thermophila fungal cell of claim 1, wherein said fungal cell has been genetically modified to reduce the catalytic efficiency of the endogenous cellobiose dehydrogenase I.

10. The Myceliophthora thermophila fungal cell of claim 9, wherein one or more residues in an active site of the cellobiose dehydrogenase I of said fungal cell has been genetically modified.

11. The Myceliophthora thermophila fungal cell of claim 10, wherein one or more residues in a heme binding domain of the cellobiose dehydrogenase I of said fungal cell have been genetically modified.

12. The Myceliophthora thermophila fungal cell of claim 1, wherein said cellobiose dehydrogenase I comprises an amino acid sequence that is at least about 85%, about 88%, about 90%, about 93%, about 95%, about 97%, about 98%, or about 99% identical to SEQ ID NO:

2.

13. The Myceliophthora thermophila fungal cell of claim 1, further comprising a cellulose degrading enzyme that is homologous or heterologous to said fungal cell.

14. A fermentation medium comprising the Myceliophthora thermophila fungal cell of claim 1.