Specific alleles important for ethanol tolerance

Abstract

The present disclosure relates to the identification of a QTL associated with high ethanol tolerance in Saccharomyces spp. More specifically, it relates to specific alleles of MKT1 and APJ1 possibly combined with a specific allele of SWS2 that are important in obtaining a high ethanol tolerance in Saccharomyces spp. It relates further to the use of such alleles in the construction of high ethanol tolerant strains, and the use of these alleles in screening for ethanol tolerance.

1 . A method of obtaining ethanol tolerance in a yeast, the method comprising:
 utilizing an inactivated APJ1 allele to obtain ethanol tolerance in the yeast.   
     
     
         2 . The method according to  claim 1 , wherein said inactivated APJ1 allele is a deletion mutant. 
     
     
         3 . The method according to  claim 1 , wherein said allele is combined with the expression of a mutant MKT1 allele. 
     
     
         4 . The method according to  claim 3 , wherein said mutant MKT1 is characterized by a glycine at position 30 and an arginine at position 453, or equivalent positions in homologous sequences. 
     
     
         5 . The method according to  claim 4 , wherein said mutant MKT1 comprises SEQ ID NO: 1. 
     
     
         6 . A method for screening ethanol resistant yeast, said method comprising:
 identifying a downregulating mutation in the APJ1 gene, and/or   determining the G30 and/or R453 mutations in the Mkt1p.   
     
     
         7 . The method according to  claim 3 , wherein the allele is combined with overexpressing a wild-type SWS2 allele. 
     
     
         8 . The method according to  claim 1 , wherein the allele is combined with:
 expressing a mutant MKT1 allele, and   overexpressing a wild-type SWS2 allele.   
     
     
         9 . The method according to  claim 1 , wherein the allele is combined with overexpressing a wild-type SWS2 allele. 
     
     
         10 . The method according to  claim 2 , wherein the allele is combined with overexpressing a wild-type SWS2 allele. 
     
     
         11 . The method according to  claim 10 , wherein the mutant MKT1 is characterized by a glycine at position 30 and an arginine at position 453, or equivalent positions in homologous sequences. 
     
     
         12 . The method according to  claim 11 , wherein the mutant MKT1 comprises SEQ ID NO: 1. 
     
     
         13 . The method according to  claim 10 , wherein the allele is combined with expressing a mutant MKT1 allele.