| 摘要 |
Alpha-amylases from Bacillus subtilis (AmyE), variants thereof, nucleic acids encoding the same, and host cells comprising the nucleic acids are provided. Methods of using AmyE or variants thereof are disclosed, including liquefaction and/or saccharification of starch. Such methods may yield sugars useful for ethanol production or high fructose corn syrup production. In some cases, the amylases can be used at low pH, in the absence of calcium, and/or in the absence of a glucoamylase. |
| 主权项 |
1. An isolated variant polypeptide having α-amylase activity and at least one altered characteristic that improves enzyme performance, wherein the altered characteristic is selected from the group consisting of increased viscosity reduction, increased amylolytic activity, increased thermostability, increased pH stability and increased stain removal, the isolated variant polypeptide comprising:
i) a polypeptide having an amino acid sequence at least 90% identical to SEQ ID NO: 1 and a modification at one or more positions selected from the group consisting of 9, 68, 88, 126, 139, 158, 192, 214, and 257 of the amino acid sequence of SEQ ID NO:1; or ii) a polypeptide having an amino acid sequence at least 92% identical to SEQ ID NO: 2, and a modification at one or more positions selected from the group consisting of 9, 68, 88, 126, 139, 158, 192, 214, and 257 of the amino acid sequence of SEQ ID NO:2, wherein the modification produces a variant polypeptide having a performance index (PI) greater than 1.0 for the at least one altered characteristic that improves enzyme performance. |
