Yeast cells having disrupted pathway from dihydroxyacetone phosphate to glycerol

Abstract

Yeast cells are genetically modified to disrupt a native metabolic pathway from dihydroxyacetone to glycerol. In certain aspects, the yeast cell is of the genera Kluyveromyces, Candida or Issatchenkia . In other aspects, the yeast cell is capable of producing at least one organic acid, such as lactate. The yeast cells produce significantly less glycerol than the wild-type strains, and usually produce greater yields of desired fermentation products. Yeast cells of the invention often grow well when cultivated, despite their curtailed glycerol production.

1 .- 69 . (canceled) 
     
     
         70 . A yeast cell of species  Issatchenkia orientalis  that is genetically modified to produce an organic acid, said yeast cell further having a deletion or disruption of (i) a native gene encoding a glycerol-3-phosphate dehydrogenase and/or a native gene encoding a glycerol-3-phosphatase, and (ii) a pyruvate decarboxylase gene. 
     
     
         71 . The yeast cell of  claim 70 , wherein the cell includes a deletion or disruption of at least one native glycerol-3-phosphate dehydrogenase gene. 
     
     
         72 . The yeast cell of  claim 70 , wherein the cell includes a deletion or disruption of at least one native glycerol-3-phosphatase gene. 
     
     
         73 . The yeast cell of  claim 72 , wherein the cell includes a deletion or disruption of at least one native glycerol-3-phosphase dehydrogenase gene and of at least one native glycerol-3-phosphatase gene. 
     
     
         74 . The yeast cell of  claim 70 , wherein the strain is capable of producing at least 70 gram/liter organic acid.