Biomass pretreatment

• US 8,546,109 B2
• Filed: 09/01/2011
• Issued: 10/01/2013
• Est. Priority Date: 03/14/2007
• Status: Active Grant

• Current Assignee: Suganit Systems, Inc., University of Toledo
• Original Assignee: Suganit Systems, Inc., University of Toledo
• Inventors: Varanasi, Sasidhar, Schall, Constance Ann, Dadi, Anantharam Prasad, Anderson, Jared, Rao, Kripa, Paripati, Praveen, Kumar, Guneet
• Primary Examiner(s): HANLEY, SUSAN MARIE
• Application Number:
  US13/224,141
• Publication Number:
  US 20120193046A1
• Time in Patent Office: 761 Days
• Field of Search: 435/72, 435/41, 435/200, 435/209, 127/37, 536/56, 162/71, 162/72
• US Class Current: 435/72
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• 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 2201/00 Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

The present invention relates to a method for lignocellulosic conversion to sugar using an ionic liquid pretreatment for the saccharification of lignocellulosic biomass. Thus, cellulose, hemicellulose, when hydrolyzed into their sugars, can be converted to ethanol fuel through well-established fermentation technologies. These sugars also form the feedstocks for production of a variety of chemical and polymers. The complex structure of the biomass required pretreatment to enable efficient saccharification of cellulose and hemicellulose components to their constituent sugars.

Claims

1. A swollen lignocellulosic biomass produced by a method comprising incubating lignocellulosic biomass comprising lignin, cellulose, and hemicellulose in an ionic liquid (IL) for a sufficient time and temperature to swell the cellulose and hemicellulose without dissolution of the biomass in the IL, wherein said time is about 5 minutes to 8 hours and said temperature ranges from about 50°

C. to 200°

C. and wherein cellulose and hemicellulose structure in the biomass is swollen at least 30% by volume compared to before the incubating step.

2. The swollen lignocellulosic biomass of claim 1, wherein said swollen lignocellulosic biomass is further washed with a liquid non-solvent for cellulose that is miscible with the IL and water.

3. The swollen lignocellulosic biomass of claim 2, wherein the liquid non-solvent for cellulose that is used for washing is water, an alcohol or acetonitrile or any solvent which dissolves the IL and thereby extracts the IL from the biomass.

4. The swollen lignocellulosic biomass of claim 3, wherein the alcohol is ethanol, methanol, butanol, or propanol.

5. The swollen lignocellulosic biomass of claim 1, wherein the ionic liquid is molten during incubation.

6. The swollen lignocellulosic biomass of claim 1, wherein the IL is any ionic liquid that is capable of disrupting the hydrogen-bonding structure of cellulose or hemicellulose represented by a cation structure that includes imidazolium, pyrroldinium, pyridinium, phosphonium, or ammonium.

7. The swollen lignocellulosic biomass of claim 1, wherein the IL is represented by the structure:

8. The swollen lignocellulosic biomass of claim 7, wherein the halide is a chloride, fluoride, bromide, or iodide.

9. The swollen lignocellulosic biomass of claim 1, wherein the IL is represented by the structure:

10. The swollen lignocellulosic biomass of claim 9, wherein the halide is a chloride, fluoride, bromide or iodide.

11. The swollen lignocellulosic biomass of claim 1, wherein the IL is 1-N-butyl-3-methylimidazolium chloride, 1-allyl-3-methyl imidazolium chloride, 3-methyl-N-butylpyridinium chloride, 1-ethyl-3-methyl imidazolium acetate, or 1-ethyl-3-methyl imidazolium propionate.

12. The swollen lignocellulosic biomass of claim 1, wherein the biomass is corn stover or poplar.

13. The swollen lignocellulosic biomass of claim 1, wherein the ionic liquid has a water content not exceeding 10%.

14. The swollen lignocellulosic biomass of claim 1, wherein the incubation temperature of the mixture is achieved by conventional heating with agitation or microwave irradiation with intermittent agitation.

15. The swollen lignocellulosic biomass of claim 1, wherein an ionic liquid mixture with a composition described by Equation 1 can be used:

16. The swollen biomass of claim 15, wherein the ionic liquid mixture comprises 1-N-butyl-3-methylimidazolium chloride ([BMIM⁺][Cl⁻

])+1-n-butyl-3-methylimidazolium chloride hexaflourophosphate ([BMIM⁺][PF₆₋

])+1-ethyl-3-methylimadazolium chloride ([EMIM⁺][Cl⁻

])+1-ethyl-3-methylimadazolium hexafluorophosphate ([EMIM⁺][PF₆₋

])+1-ethyl-3-methylimadazolium tetrafluoroborate ([EMIM⁺][BF₄⁻

]).

17. The swollen lignocellulosic biomass of claim 1, wherein the temperature is 120°

C.

18. The swollen lignocellulosic biomass of claim 1, wherein the temperature is 130°

C.

19. The swollen lignocellulosic biomass of claim 1, wherein the temperature is 150°

C.