Methods of hydrolyzing a cellulose using halophilic, thermostable and ionic liquids tolerant cellulases
The present invention provides for an isolated or recombinant polypeptide comprising an amino acid sequence having at least 70% identity with the amino acid sequence of a Halorhabdus utahensis cellulase, such as Hu-CBH1, wherein said amino acid sequence has a halophilic thermostable and/or thermophilic cellobiohydrolase (CBH) activity. In some embodiments, the polypeptide has a CBH activity that is resistant to up to about 20% of ionic liquids. The present invention also provides for compositions comprising and methods using the isolated or recombinant polypeptide.
1. A method of hydrolyzing a cellulose, comprising: (a) providing a composition comprising (i) an isolated or recombinant polypeptide comprising an amino acid sequence having at least 90% identity with the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:5, wherein said isolated or recombinant polypeptide comprises a catalytic domain, a fibronectin domain 3 (FN-3) and an Ig-like domain, and has a halophilic thermostable or thermophilic cellobiohydrolase (CBH) activity, (ii) a suitable salt concentration, (iii) an ionic liquid (IL), and (iv) a cellulose; and (b) incubating the composition for a suitable length of time, such that the cellulose is hydrolyzed by the polypeptide.
2. The method of claim 1 , wherein the composition comprises a pretreatment biomass.
3. The method of claim 1 , wherein the amino acid sequence has at least 95% identity with the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:5.
4. The method of claim 3 , wherein the amino acid sequence has at least 99% identity with the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:5.
5. The polypeptide of claim 4 , wherein the amino acid sequence of the polypeptide comprises the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:5.
6. The method of claim 2 , wherein the composition has a temperature of from about 37° C. to about 90° C.
7. The method of claim 6 , wherein the composition has a temperature of from about 50° C. to about 90° C.
8. The method of claim 7 , wherein the composition has a temperature of from about 60° C. to about 90° C.
9. The method of claim 2 , wherein the composition has a NaCl, or other suitable salt, or mixture thereof, concentration of from about 0.1 M to about 5 M.
10. The method of claim 9 , wherein the composition has a NaCl, or other suitable salt, or mixture thereof, concentration of from about 2 M to about 5 M.
11. The method of claim 2 , wherein the composition has a pH of from 7.5 to 12.5.
12. The method of claim 11 , wherein the composition has a pH of equal to or more than about 8 pH.
13. The method of claim 2 , wherein the composition has a concentration of IL equal to or more than 1% w/w.
14. The method of claim 13 , wherein the composition has a concentration of IL of 20 to 30%.
15. The method of claim 2 , wherein the composition comprises 1-alkyl-3-alkylimidazolium alkanate, 1-alkyl-3-alkylimidazolium alkylsulfate, 1-alkyl-3-alkylimidazolium methylsulfonate, 1-alkyl-3-alkylimidazolium hydrogensulfate, 1-alkyl-3-alkylimidazolium thiocyanate, or 1-alkyl-3-alkylimidazolium halide, wherein an “alkyl” is an alkyl group comprising from 1 to 10 carbon atoms, and an “alkanate” is an alkanate comprising from 1 to 10 carbon atoms.
16. The method of claim 15 , wherein the composition comprises 1-allyl-3-methylimidazolium acetate (AMIM Acetate), 1-allyl-3-methylimidazolium chloride (AMIM Cl), 1-allyl-3-methylimidazolium hydrogensulfate (AMIM HOSO 3 ), 1-allyl-3-methylimidazolium methylsulfate (AMIM MeOSO 3 ), 1-allyl-3-methylimidazolium ethylsulfate (AMIM EtOSO 3 ), 1-allyl-3-methylimidazolium methanesulfonate (AMIM MeSO 3 ), 1-allyl-3-methylimidazolium tetrachloroaluminate (AMIM AlCl 4 ), 1-ethyl-3-methylimidazolium acetate (EMIM Acetate), 1-ethyl-3-methylimidazolium chloride (EMIM Cl), 1-ethyl-3-methylimidazolium hydrogensulfate (EMIM HOSO 3 ), 1-ethyl-3-methylimidazolium methylsulfate (EMIM MeOSO 3 ), 1-ethyl-3-methylimidazolium ethylsulfate (EMIM EtOSO 3 ), 1-ethyl-3-methylimidazolium methanesulfonate (EMIM MeSO 3 ), 1-ethyl-3-methylimidazolium tetrachloroaluminate (EMIM AlCl 4 ), 1-ethyl-3-methylimidazolium thiocyanate (EMIM SCN), 1-butyl-3-methylimidazolium acetate (BMIM Acetate), 1-butyl-3-methylimidazolium chloride (BMIM Cl), 1-butyl-3-methylimidazolium hydrogensulfate (BMIM HOSO 3 ), 1-butyl-3-methylimidazolium methanesulfonate (BMIM MeSO 3 ), 1-butyl-3-methylimidazolium methylsulfate (BMIM MeOSO 3 ), 1-butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl 4 ), 1-butyl-3-methylimidazolium thiocyanate (BMIM SCN), 1-ethyl-2,3-dimethylimidazolium ethylsulfate (EDIM EtOSO 3 ), Tris(2-hydroxyethyl)methylammonium methylsulfate (MTEOA MeOSO 3 ), 1-methylimidazolium chloride (MIM Cl), 1-methylimidazolium hydrogensulfate (MIM HOSO 3 ), 1,2,4-trimethylpyrazolium methylsulfate, tributylmethylammonium methylsulfate, choline acetate, choline salicylate, or a mixture thereof.
17. The method of claim 2 , wherein the incubating step results in at least 50% hydrolysis of the cellulose into cellobioses.
18. The method of claim 17 , wherein the incubating step results in at least 70% hydrolysis of the cellulose into cellobioses.