Ammonium based ionic liquids useful for lignocellulosic processing

1. A method for treating a biomass comprising polysaccharide and lignin, the method comprising:

(i) providing a pre-treatment mixture comprising the biomass at a concentration of at least about 5% (w/w) and an ionic liquid at a concentration of at least about 40% w/w, wherein the pre-treatment mixture comprises a single ionic liquid, and wherein the single ionic liquid comprises TBAOH;

(ii) maintaining the mixture under pre-treatment conditions sufficient to dissolve at least a portion of the polysaccharide present in the biomass, wherein the pre-treatment conditions comprise a temperature of at least about 20° C. and less than about 55° C. for a duration of from about 0.5 hours to about 3 hours, wherein the temperature is maintained with about 10 MT/hr to about 40 MT/hr of steam.

2. A method for treating a biomass comprising polysaccharide and lignin, the method comprising:

(i) providing a pre-treatment mixture comprising the biomass at a concentration of at least about 5% (w/w) and an ionic liquid at a concentration of at least about 40% w/w, wherein the ionic liquid comprises:

a) a quaternary ammonium cation comprising four alkyl groups covalently linked to the ammonium cation, wherein each of the four alkyl groups is independently C 1 -C 6 alkyl; and

b) an anion selected from the group consisting of OH − , HSO 4 − , H 2 PO 4 − , PO 4 − , lysinate, HCO 3 − , and Cl − ;

(ii) maintaining the mixture under pre-treatment conditions sufficient to dissolve at least a portion of the polysaccharide present in the biomass, wherein the pre-treatment conditions comprise a temperature of at least about 20° C. and less than about 55° C. for a duration of from about 0.5 hours to about 3 hours, and wherein the pre-treatment conditions comprise maintaining the temperature of the pre-treatment mixture with about 10 MT/hr to about 40 MT/hr of steam to process 2000 MT/day of dry biomass.

3. A method for treating a biomass comprising polysaccharide and lignin, the method comprising:

(i) providing a pre-treatment mixture comprising the biomass at a concentration of at least about 5% (w/w) and an ionic liquid at a concentration of at least about 40% w/w,

wherein the ionic liquid comprises:

a) a quaternary ammonium cation comprising four alkyl groups covalently linked to the ammonium cation, wherein each of the four alkyl groups is independently C 1 -C 6 alkyl; and

b) an anion selected from the group consisting of OH − , HSO 4 − , H 2 PO 4 − , PO 4 − , lysinate, HCO 3 − , and Cl − , and

wherein the biomass is derived from switchgrass, Miscanthus , corn stover, corn fiber, rice hulls, hard wood, softwood, municipal solid waste, industrial organic waste, office paper, or mixtures thereof;

(ii) maintaining the mixture under pre-treatment conditions sufficient to dissolve at least a portion of the polysaccharide present in the biomass, wherein the pre-treatment conditions comprise a temperature c; and wherein the pre-treatment conditions comprise maintaining the temperature of the pre-treatment mixture with about 10 MT/hr to about 40 MT/hr of steam to process 2000 MT/day of dry biomass.

4. The method of claim 1 , wherein the pre-treatment mixture comprises an ionic liquid comprising a tetrabutylammonium (TBA) cation.

5. The method of claim 1 , wherein the anion of the ionic liquid is OH − .

6. The method of claim 1 , wherein the ionic liquid is at a concentration of between about 40% and about 90% w/w.

7. The method of claim 1 , wherein after (ii), the method further comprises:

(iii) diluting the pre-treatment mixture with a polar solvent.

8. The method of claim 7 , wherein the polar solvent is selected from the group consisting of water, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octonol, and isooctonol.

9. The method of claim 7 , wherein step (iii) further comprises reducing the pH of the pre-treatment mixture with an acid, and after diluting the pre-treatment mixture, the method comprises:

(iv) contacting the diluted pre-treated mixture with a glycoside hydrolase under conditions sufficient to hydrolyze at least a portion of glucan, thereby forming a sugar composition, wherein the sugar composition comprises at least one monosaccharide or oligosaccharide.

10. The method of claim 9 , wherein the glycoside hydrolase comprises a cellulase.

11. The method of claim 9 , wherein the glycoside hydrolase is selected from the group consisting of an endoglucanase, an exoglucanase, a β-glucosidase, a xylanase, and mixtures thereof.

12. The method of claim 7 , wherein after diluting the pre-treatment mixture, the method comprises:

(iv) collecting pre-treated biomass solids from the mixture, wherein the pre-treated biomass solids comprise at least about 50% of glucan present in the biomass provided in the pretreatment mixture.

13. The method of claim 12 , wherein the method further comprises:

(v) contacting the pre-treated biomass solids with a glycoside hydrolase under conditions sufficient to hydrolyze at least a portion of glucan, thereby forming a sugar composition, wherein the sugar composition comprises at least one monosaccharide or oligosaccharide.

14. The method of claim 13 , wherein the glycoside hydrolase comprises a cellulase.

15. The method of claim 13 , wherein the glycoside hydrolase is selected from the group consisting of an endoglucanase, an exoglucanase, a β-glucosidase, a xylanase, and mixtures thereof.