Patent

1. An isolated polypeptide comprising (i) residues 21-463 of SEQ ID NO:3, or (ii) a variant of Trichoderma reesei α-amylase (TrAA), wherein the variant has α-amylase activity and at least 95% amino acid sequence identity to residues 21-463 of SEQ ID NO:3.

2. A method of saccharifying liquefied starch to produce a maltose-rich syrup comprising: adding a polypeptide according to claim 1 to a liquefied starch solution, and saccharifying the liquefied starch solution, wherein said saccharifying the liquefied starch solution produces a maltose-rich syrup.

3. The method of claim 2 , wherein said polypeptide is added to the liquefied starch solution at about 0.3-1 kg per metric ton of dry solids.

4. The method of claim 2 , wherein the liquefied starch solution is a slurry of liquefied starch at about 20-35% w/w dry solids.

5. The method of claim 2 , wherein the liquefied starch solution is saccharified at about 50° C. to about 60° C.

6. The method of claim 5 , wherein the liquefied starch solution is saccharified at about 55° C. to about 60° C.

7. The method of claim 2 , wherein the liquefied starch solution is saccharified at about pH 4.0 to about pH 6.0.

8. The method of claim 7 , wherein the liquefied starch solution is saccharified at about pH 4.2 to about pH 4.8.

9. The method of claim 2 , further comprising a step of adding a pullulanase, a β-amylase, a fungal α-amylase that is not a TrAA, a protease, a cellulase, a hemicellulase, a lipase, a cutinase, an isoamylase, or a combination thereof, to the liquefied starch solution.

10. The method of claim 2 , wherein the final concentration of maltose reaches a weight percent of dry solids of about 50% to about 62%.

11. The method of claim 10 , wherein the final concentration of maltose reaches a weight percent of dry solids of about 60% to about 62%.