Transgenic plants containing ligninase and cellulase which degrade lignin and cellulose to fermentable sugars

• US 7,423,195 B2
• Filed: 02/14/2006
• Issued: 09/09/2008
• Est. Priority Date: 10/20/2000
• Status: Expired due to Fees

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Dale, Bruce E., Sticklen, Masomeh B., Magbool, Shahina B.
• Primary Examiner(s): Kallis; Russell
• Application Number:
  US11/354,310
• Publication Number:
  US 20060185037A1
• Time in Patent Office: 938 Days
• Field of Search: None
• US Class Current: 800/288
• CPC Class Codes: C12N 15/8207 by mechanical means, e.g. microinjection, particle bombardment, silicon whiskers
• CPC Class Codes: C12N 15/8242 with non-agronomic quality (output) traits, e.g. for industrial processing; Value added, non-agronomic traits
• CPC Class Codes: C12N 15/8246 Non-starch polysaccharides, e.g. cellulose, fructans, levans
• CPC Class Codes: C12N 15/8255 involving lignin biosynthesis
• CPC Class Codes: C12N 15/8257 for the production of primary gene products, e.g. pharmaceutical products, interferon
• 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 19/14 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 7/06 Ethanol, i.e. non-beverage
• CPC Class Codes: C12Y 302/01004 Cellulase (3.2.1.4), i.e. endo-1,4-beta-glucanase
• CPC Class Codes: C12Y 302/01011 Dextranase (3.2.1.11)
• CPC Class Codes: C12Y 302/01021 Beta-glucosidase (3.2.1.21)
• CPC Class Codes: C12Y 302/01091 Cellulose 1,4-beta-cellobiosidase (3.2.1.91)
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

The present invention provides transgenic plants which after harvest degrade the lignin and cellulose therein to fermentable sugars which can further be fermented to ethanol or other products. In particular, the transgenic plants comprise ligninase and cellulase genes from microbes operably linked to a DNA encoding a signal peptide which targets the fusion polypeptide produced therefrom to an organelle of the plant, in particular the chloroplasts. When the transgenic plants are harvested, the plants are ground to release the ligninase and cellulase which then degrade the lignin and cellulose of the transgenic plants to produce the fermentable sugars.

Claims

1. A transgenic plant which degrades lignins when the transgenic plant is ground to produce a plant material comprising:

at least one DNA comprising the nucleotide sequence set forth in SEQ ID NO;

13 encoding a ligninase which is ckg5 which is operably linked to a nucleotide seguence encoding a signal peptide wherein the signal peptide directs the ligninase to an organelle of the transgenic plant wherein the transgenic plant degrades the lignins when ground to produce the plant material.

2. The transgenic plant of claim 1 wherein the DNA encoding the ligninase is from Phanerochaete chrysosporium.

3. The transgenic plant of claim 1 wherein the DNA encoding the ligninase is operably linked to a leaf-specific promoter.

4. The transgenic plant of claim 3 wherein the leaf-specific promoter is a promoter for rbcS.

5. The transgenic plant of claim 1 wherein the nucleotide sequence encoding the signal peptide encodes a signal peptide of rbcS.

6. The transgenic plant of claim 4 or 5 wherein the rbcS comprises the nucleotide sequence set forth in SEQ ID NO:

1.

7. The transgenic plant of claim 1 selected from the group consisting of maize, wheat, barley, rye, hops, hemp, rice, potato, soybean, sorghum, sugarcane, clover, tobacco, alfalfa, arabidopsis, coniferous tree, and deciduous tree.

8. The transgenic plant of claim 1 wherein the DNA is stably integrated into nuclear or plastid DNA of the transgenic plant.

9. The transgenic plant of claim 1 wherein the transgenic plant further includes a DNA encoding a selectable marker operably linked to a constitutive promoter.

10. The transgenic plant of claim 9 wherein the DNA encoding the selectable marker provides the transgenic plant with resistance to an antibiotic, an herbicide, or to environmental stress.

11. The transgenic plant of claim 10 wherein the DNA encoding resistance to the herbicide is a DNA encoding phosphinothricin acetyl transferase which confers resistance to the herbicide phosphinothricin.

12. The transgenic plant of claim 1 wherein the organelle of the plant is selected from the group consisting of nucleus, microbody, endoplasmic reticulum, endosome, vacuole, mitochondria, chloroplast, or plastid.

13. The transgenic plant of claim 1 wherein the organelle of the plant is the chloroplast.