Enzymes Having Alpha Amylase Activity and Methods of Making and Using Them

Abstract

The invention relates to alpha amylases and to polynucleotides encoding the alpha amylases. In addition, methods of designing new alpha amylases and methods of use thereof are also provided. The alpha amylases have increased activity and stability at acidic, neutral and alkaline pH and increased temperature.

What is claimed is: 
     
         1 : A variant polypeptide comprising: an amino acid sequence having at least one amino acid substitution compared to SEQ ID NO:120, and at least 95% sequence identity to SEQ ID NO:120; wherein the variant polypeptide has alpha-amylase activity. 
     
     
         2 : A method of hydrolyzing a polysaccharide or oligosaccharide having alpha 1,4 glucosidic linkages comprising: (a) providing the polypeptide of  claim 1 , and (b) contacting a substance containing the polysaccharide or oligosaccharide with the polypeptide of  claim 1 , under conditions which facilitate the hydrolysis of the alpha 1,4 glucosidic linkages polysaccharide or oligosaccharide. 
     
     
         3 : A method for textile desizing comprising: (a) providing the polypeptide of  claim 1 , and (b) contacting a textile with the polypeptide of (a) under conditions effective for said desizing. 
     
     
         4 : A method for producing a high-maltose, a high-glucose syrup or a mixed syrup comprising: (a) providing the polypeptide of  claim 1 , and (b) liquefying a starch using an effective amount of the polypeptide of (a) to obtain a soluble starch hydrolysate; and saccharifying the soluble starch hydrolysate, thereby producing a high-maltose, a high-glucose syrup or a mixed syrup. 
     
     
         5 : A method for making ethanol comprising: (a) providing the polypeptide of  claim 1 ; (b) contacting a composition comprising a starch with the polypeptide of (a), to produce a starch hydrolysate; and, (c) fermenting the starch hydolysate of (b) to produce ethanol. 
     
     
         6 : A method for dry milling comprising: (a) providing the polypeptide of  claim 1 , and (b) contacting a whole ground grain with the polypeptide of (a), under conditions sufficient for the polypeptide to hydrolyze a starch in the whole ground grain. 
     
     
         7 : A method for liquefying a starch comprising: (a) providing the polypeptide of  claim 1 ; (b) providing a composition comprising the starch; and, (c) contacting the composition of (b) with the polypeptide of (a), under conditions wherein the polypeptide liquefies the starch. 
     
     
         8 : A composition comprising the polypeptide of  claim 1 , wherein the composition is a detergent, a detergent additive, a food, a food supplement, a feed supplement, or a feed.