Compositions and methods for 3-hydroxypropionic acid production

Abstract

The present application discloses genetically modified yeast cells comprising an active 3-HP fermentation pathway, and the use of these cells to produce 3-HP.

What is claimed is: 
     
         1 . A genetically modified yeast cell comprising an active 3-HP fermentation pathway, wherein the cell is capable of growing at a pH of less than 4 in media containing 75 g/L or greater 3-HP. 
     
     
         2 . The genetically modified yeast cell of  claim 1 , wherein the cell is capable of growing at a pH of less than 4 in media containing 100 g/L or greater 3-HP. 
     
     
         3 . The genetically modified yeast cell of  claim 1 , wherein the cell is a 3-HP-resistant yeast cell. 
     
     
         4 . The genetically modified yeast cell of  claim 1 , wherein the cell is capable of growing at a pH of less than 4 in media containing 100 g/L or greater 3-HP. 
     
     
         5 . The genetically modified yeast cell of  claim 1 , comprising an exogenous PYC gene. 
     
     
         6 . The genetically modified yeast cell of  claim 1 , wherein the cell has undergone mutation and/or selection, such that the mutated and/or selected cell possess a higher degree of resistance to 3-HP than a wild-type cell of the same species. 
     
     
         7 . The genetically modified yeast cell of  claim 6 , wherein the cell has undergone mutation and/or selection before being genetically modified with the one or more exogenous 3-HP pathway genes. 
     
     
         8 . The genetically modified yeast cell of  claim 6 , wherein the cell has undergone selection in the presence of lactic acid or 3-HP. 
     
     
         9 . The genetically modified yeast cell of  claim 8 , wherein the selection is chemostat selection. 
     
     
         10 . The genetically modified yeast cell of  claim 1 , wherein said cell is Crabtree-negative. 
     
     
         11 . The genetically modified yeast cell of  claim 1 , wherein the cell belongs to a genus selected from  Issatchenkia, Candida, Kluyveromyces, Pichia, Schizosaccharomyces, Torulaspora, Zygosaccharomyces , and  Saccharomyces.    
     
     
         12 . The genetically modified yeast cell of  claim 11 , wherein the cell belongs to a clade selected from the  I. orientalis/P. fermentans  clade and the  Saccharomyces  clade. 
     
     
         13 . The genetically modified yeast cell of  claim 11 , wherein the cell is selected from  I. orientalis, C. lambica , and  S. bulderi.    
     
     
         14 . The genetically modified yeast cell of  claim 11 , wherein the cell an  I. orientalis  CNB1 yeast cell. 
     
     
         15 . The genetically modified yeast cell of  claim 1 , wherein the cell is unable to ferment pentose sugars. 
     
     
         16 . A method of producing 3-HP comprising:
 (i) culturing the genetically modified yeast cell of  claim 1  in the presence of medium comprising at least one carbon source; and   (ii) isolating 3-HP from the culture.   
     
     
         17 . The method of  claim 16 , wherein said carbon source is selected from glucose, xylose, arabinose, sucrose, fructose, cellulose, glucose oligomers, and glycerol. 
     
     
         18 . The method of  claim 16 , wherein the medium is at a pH of less than 5. 
     
     
         19 . The method of  claim 16 , wherein the modified yeast cell is an  I. orientalis  CNB1 yeast cell. 
     
     
         20 . The method of  claim 16 , wherein the modified yeast cell is unable to ferment pentose sugars.