Thermostable Alpha-Amylases

Abstract

The present invention relates to an isolated polynucleotide comprising an open reading frame encoding a polypeptide having alpha-amylase activity, the polypeptide selected from the group consisting of: a) a polypeptide comprising an amino acid sequence which has at least 70% identity with amino acids 22 to 450 of SEQ ID NO: 4; b) a polypeptide comprising an amino acid sequence which has at least 70% identity with the polypeptide encoded by the amylase encoding part of the polynucleotide inserted into a plasmid present in the E. coli host deposited under the Budapest Treaty with DSMZ under accession number DSM 15334; c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence which has at least 70% identity with the sequence shown from position 68 to 1417 in SEQ ID NO: 3; and d) a fragment of (a), (b) or (c) that has alpha-amylase activity.

1 . An isolated polynucleotide comprising an open reading frame encoding a polypeptide having alpha-amylase activity, the polypeptide selected from the group consisting of:
 a) a polypeptide comprising an amino acid sequence which has at least 70% identity with amino acids 22 to 450 of SEQ ID NO: 4;   b) a polypeptide comprising an amino acid sequence which has at least 70% identity with the polypeptide encoded by the amylase encoding part of the polynucleotide inserted into a plasmid present in the  E. coli  host deposited under the Budapest Treaty with DSMZ under accession number DSM 15334;   c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence which has at least 70% identity with the sequence shown from position 68 to 1417 in SEQ ID NO: 3; and   d) a fragment of (a), (b) or (c) that has alpha-amylase activity.   
     
     
         2 . The polynucleotide of  claim 1 , wherein the polypeptide is an artificial variant comprising an amino acid sequence that has one or more truncation(s), and/or at least one substitution, deletion, and/or insertion of an amino acid as compared to amino acids 22 to 450 of SEQ ID NO: 4. 
     
     
         3 . The polynucleotide of  claim 1 , wherein the polypeptide comprises an amino acid sequence which has at least 70% identity with amino acids 22 to 450 of SEQ ID NO: 4. 
     
     
         4 . The polynucleotide of  claim 1 , wherein the polypeptide comprises the amino acids 22 to 450 of SEQ ID NO: 4. 
     
     
         5 . The polynucleotide of  claim 1 , wherein the polypeptide consists of the amino acids 22 to 450 of SEQ ID NO: 4. 
     
     
         6 . The polynucleotide of  claim 1 , wherein the polypeptide comprises an amino acid sequence which has at least 70% identity with the polypeptide encoded by the amylase encoding part of the nucleotide sequence inserted into a plasmid present in the  E. coli  host deposited under the Budapest Treaty with DSMZ under accession number DSM 15334. 
     
     
         7 . The polynucleotide of  claim 6 , wherein the polypeptide comprises the amino acid sequence encoded by the amylase encoding part of the nucleotide sequence inserted into a plasmid present in the  E. coli  host deposited under the Budapest Treaty with DSMZ under accession number DSM 15334. 
     
     
         8 . The polynucleotide of  claim 6 , wherein the polypeptide consists of the amino acid sequence encoded by the amylase encoding part of the nucleotide sequence inserted into a plasmid present in the  E. coli  host deposited under the Budapest Treaty with DSMZ under accession number DSM 15334. 
     
     
         9 . The polynucleotide of  claim 6 , wherein the polypeptide is an artificial variant which comprises an amino acid sequence that has one or more truncation(s), and/or at least one substitution, deletion, and/or insertion of an amino acid as compared to the amino acid sequence encoded by the amylase encoding part of the nucleotide sequence inserted into a plasmid present in the  E. coli  host deposited under the Budapest Treaty with DSMZ under accession number DSM 15334. 
     
     
         10 . A nucleic acid construct comprising a polynucleotide of  claim 1  operably linked to one or more control sequences that direct the production of the polypeptide in a suitable host cell. 
     
     
         11 . A recombinant expression vector comprising a nucleic acid construct of  claim 10 . 
     
     
         12 . A recombinant host cell comprising a nucleic acid construct of  claim 10 . 
     
     
         13 - 16 . (canceled) 
     
     
         17 . A method for producing a polypeptide having alpha-amylase activity, the method comprising:
 (a) cultivating a recombinant host cell of  claim 12  under conditions conducive for production of the polypeptide; and   (b) recovering the polypeptide.   
     
     
         18 . A method of producing an enzymatically modified starch derivative, wherein a polypeptide having alpha-amylase activity produced according to a method of  claim 17  is used for liquefying and/or saccharifying starch. 
     
     
         19 . A method of producing high maltose syrups, wherein a polypeptide having alpha-amylase activity produced according to a method of  claim 17  is used for liquefying starch. 
     
     
         20 . A process for producing an alcohol, comprising liquefying a starch with a polypeptide having alpha-amylase activity produced according to a method of  claim 17 . 
     
     
         21 . An isolated polypeptide having alpha-amylase activity, selected from the group consisting of:
 a) a polypeptide with at least 70% sequence identity with amino acids 22 to 450 of SEQ ID NO: 4;   b) a polypeptide encoded by a polynucleotide with at least 70% sequence identity with the sequence of nucleotides 68 to 1417 of SEQ ID NO: 3; and   c) a fragment of (a) that has alpha-amylase activity.   
     
     
         22 . The polypeptide of  claim 21 , comprising amino acids 22 to 450 of SEQ ID NO: 4. 
     
     
         23 . The polypeptide of  claim 21 , consisting of the amino acids 22 to 450 of SEQ ID NO: 4.