Ionic liquid-tolerant cellulase enzymes
The present invention provides ionic liquid-tolerant cellulases and method of producing and using such cellulases. The cellulases of the invention are useful in saccharification reactions using ionic liquid treated biomass.
1. A composition comprising: (i) an ionic-liquid-tolerant β-glucosidase comprising an amino acid sequence having at least 99% sequence identity to the amino acid sequence of SEQ ID NO:2 and having β-glucosidase activity; (ii) an ionic liquid that has an imidazolium cation: and (iii) a lignocellulosic biomass.
2. The composition of claim 1 , wherein the ionic liquid is [C 2 mim][OAc].
3. The composition of claim 1 , wherein the ionic-liquid-tolerant β-glucosidase comprises the amino acid sequence of SEQ ID NO:2.
4. The composition of claim 1 , further comprising soluble sugars.
5. The composition of claim 3 , wherein the ionic liquid is [C 2 mim][OAc].
6. The composition of claim 1 , further comprising at least one ionic-liquid-tolerant endoglucanase comprising an amino acid sequence selected from the group consisting of SEQ ID NOS:16-26.
7. A method of increasing the yield of soluble sugar from a lignocellulosic biomass, the method comprising incubating lignocellulosic biomass with a composition comprising an ionic-liquid-tolerant β-glucosidase and an ionic liquid having an imidazolium cation in an enzymatic hydrolysis reaction, wherein the ionic-liquid-tolerant β-glucosidase comprises an amino acid sequence having at least 99% sequence identity to the amino acid sequence of SEQ ID NO:2 and has β-glucosidase activity.
8. The method of claim 7 , wherein the biomass is pretreated with ionic liquid.
9. The method of claim 7 , wherein the ionic liquid is [C 2 mim][OAc].
10. The composition of claim 6 , wherein the ionic liquid-tolerant endoglucanase comprises an amino acid sequence selected from the group consisting of SEQ ID NO:16, 17, 18, 19, 20, and 21.
11. The composition of claim 6 , wherein the ionic liquid-tolerant endoglucanase comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 17, 18, and 21.
12. The method of claim 7 , wherein the ionic-liquid-tolerant β-glucosidase comprises the amino acid sequence of SEQ ID NO:2.
13. The method of claim 7 , wherein the enzymatic hydrolysis reaction further comprises at least one ionic-liquid-tolerant endoglucanase comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 16-26.
14. The method of claim 13 , wherein the ionic-liquid-tolerant endoglucanase comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 16, 17, 18, 19, 20, and 21.
15. The method of claim 13 , wherein the ionic-liquid-tolerant endoglucanase comprises an amino acid sequence selected from the group consisting of SEQ ID NO: 17, 18, and 21.