Glucoamylase Variants

Abstract

The invention relates to a variant of a parent fungal glucoamylase, which exhibits improved thermal stability and/or increased specific activity using saccharide substrates.

1 - 22 . (canceled) 
     
     
         23 . A non-naturally occurring variant of a parent glucoamylase comprising an insertion at one or more positions selected from the group consisting of:
 409, 410, 411, 412, 413, and 414;   wherein
 (a) the parent glucoamylase has at least 90% sequence identity with SEQ ID NO: 2; 
 (b) the variant has 1-5 alterations compared to the parent glucoamylase; and 
 (c) the variant has glucoamylase activity. 
   
     
     
         24 . The variant of  claim 23 , which comprises an insertion at position 409. 
     
     
         25 . The variant of  claim 23 , which comprises an insertion at position 410. 
     
     
         26 . The variant of  claim 23 , which comprises an insertion at position 411. 
     
     
         27 . The variant of  claim 23 , which comprises an insertion at position 412. 
     
     
         28 . The variant of  claim 23 , which comprises an insertion at position 413. 
     
     
         29 . The variant of  claim 23 , which comprises an insertion at position 414. 
     
     
         30 . The variant of  claim 23 , which has an altered thermal stability compared to the parent glucoamylase. 
     
     
         31 . The variant of  claim 23 , which has an altered specific activity compared to the parent glucoamylase. 
     
     
         32 . The variant of  claim 23 , further comprising one or more alterations in one or more regions selected from the group consisting of one or more substitution(s), insertion(s) and/or deletion(s) in: Region: 36-39, Region: 63-65, Position 67, Region: 69-71, Region: 81-92, Region: 128-169, Region: 185-188, Region: 190-199, Region: 213-222, Region: 224-226, Region: 228-233, Region: 247-271, Region: 273-286, Region: 320-333, Region: 343-344, Region: 346-347, Region: 349-351, Region: 375-378, Region: 380-385, Position: 387, Position: 415, Region: 417-424, Position: 426, Region: 428-443, Region: 471-485, Region: 487-489, Region: 491-493. 
     
     
         33 . The variant of  claim 23 , wherein the parent glucoamylase has at least 95% sequence identity with SEQ ID NO: 2. 
     
     
         34 . The variant of  claim 23 , wherein the parent glucoamylase has the sequence of amino acids 1-510 of SEQ ID NO: 2. 
     
     
         35 . The variant of  claim 23 , wherein the parent glucoamylase is a truncated glucoamylase. 
     
     
         36 . A process for converting starch or partially hydrolyzed starch into a syrup containing dextrose, said process comprising saccharifying a starch hydrolyzate in the presence of a variant of  claim 23 . 
     
     
         37 . A method of saccharifying a liquefied starch solution, which method comprises:
 (a) a saccharification wherein one or more enzymatic saccharification stages takes place, and   (b) one or more high temperature membrane separation steps, wherein the enzymatic saccharification is carried out using a variant of  claim 23 .