Yeast organism producing isobutanol at a high yield

Abstract

There is disclosed a method of producing isobutanol. In an embodiment, the method includes providing a microorganism transformed with an isobutanol producing pathway containing at least one exogenous gene. The microorganism is selected to produce isobutanol from a carbon source at a yield of at least 10 percent theoretical. The method includes cultivating the microorganism in a culture medium containing a feedstock providing the carbon source, until isobutanol is produced. The method includes recovering the isobutanol. In one embodiment, the microorganism is a yeast with a Crabtree-negative phenotype. In another embodiment, the microorganism is a yeast microorganism with a Crabtree-positive phenotype. There is disclosed a microorganism for producing isobutanol. In an embodiment, the microorganism includes an isobutanol producing pathway containing at least one exogenous gene, and is selected to produce a recoverable quantity of isobutanol from a carbon source at a yield of at least 10 percent theoretical.

1 . A microorganism for producing isobutanol, the microorganism comprising: an isobutanol producing pathway containing at least one exogenous gene, the microorganism selected to produce a recoverable quantity of isobutanol from a carbon source at a yield of at least 10 percent theoretical, and wherein the microorganism is transformed to reduce pyruvate decarboxylase (PDC) activity and glycerol 3-phosphate dehydrogenase (GPD) activity. 
     
     
         2 . A microorganism in accordance with  claim 1 , wherein the microorganism is transformed to eliminate pyruvate decarboxylase (PDC) activity and glycerol 3-phosphate dehydrogenase (GPD) activity. 
     
     
         3 . A microorganism in accordance with  claim 1 , wherein the microorganism is transformed to delete a positive transcriptional regulator for structural gene encoding for pyruvate decarboxylase (PDC) and to delete a positive transcriptional regulator for structural gene encoding for glycerol 3-phosphate dehydrogenase (GPD). 
     
     
         4 . A microorganism in accordance with  claim 1 , wherein the microorganism is transformed by deleting a pyruvate decarboxylase (PDC) gene and by deleting a glycerol 3-phosphate dehydrogenase (GPD) gene. 
     
     
         5 . A microorganism in accordance with  claim 1 , wherein the microorganism is transformed to delete all pyruvate decarboxylase (PDC) genes and to delete all glycerol 3-phosphate dehydrogenase (GPD) genes. 
     
     
         6 . A microorganism in accordance with  claim 1 , wherein the microorganism expresses a heterologous metabolic pathway for conversion of pyruvate to isobutanol. 
     
     
         7 . A microorganism in accordance with  claim 1 , wherein the microorganism is selected to produce the isobutanol at the yield of at least about 70% theoretical. 
     
     
         8 . A microorganism in accordance with  claim 1 , wherein the microorganism has increased capacity to produce acetolactate. 
     
     
         9 . A microorganism in accordance with  claim 1 , wherein the microorganism is a yeast with a Crabtree-negative phenotype. 
     
     
         10 . A microorganism in accordance with  claim 1 , wherein the microorganism is a yeast with a Crabtree-positive phenotype. 
     
     
         11 . A microorganism in accordance with  claim 10 , wherein the microorganism is an engineered  S. cerevisiae  yeast. 
     
     
         12 . A method of producing isobutanol, comprising:
 (a) providing a microorganism transformed with an isobutanol producing pathway containing at least one exogenous gene, the microorganism selected to produce the isobutanol from a carbon source at a yield of at least 10 percent theoretical, and wherein the microorganism is transformed to reduce pyruvate decarboxylase (PDC) activity and glycerol 3-phosphate dehydrogenase (GPD) activity;   (b) cultivating the microorganism in a culture medium containing a feedstock providing the carbon source, until a recoverable quantity of the isobutanol is produced; and   (c) recovering the isobutanol.   
     
     
         13 . A method in accordance with  claim 12 , wherein the microorganism is transformed to eliminate pyruvate decarboxylase (PDC) activity and glycerol 3-phosphate dehydrogenase (GPD) activity. 
     
     
         14 . A method in accordance with  claim 12 , wherein the microorganism is transformed to delete a positive transcriptional regulator for structural gene encoding for pyruvate decarboxylase (PDC) and to delete a positive transcriptional regulator for structural gene encoding for glycerol 3-phosphate dehydrogenase (GPD). 
     
     
         15 . A method in accordance with  claim 12 , wherein the microorganism is transformed by deleting a pyruvate decarboxylase (PDC) gene and by deleting a glycerol 3-phosphate dehydrogenase (GPD) gene. 
     
     
         16 . A method in accordance with  claim 12 , wherein the microorganism is transformed to delete all pyruvate decarboxylase (PDC) genes and to delete all glycerol 3-phosphate dehydrogenase (GPD) genes. 
     
     
         17 . A method in accordance with  claim 12 , wherein the microorganism expresses a heterologous metabolic pathway for conversion of pyruvate to isobutanol. 
     
     
         18 . A method in accordance with  claim 12 , wherein the microorganism is selected to produce the isobutanol at the yield of at least about 70% theoretical. 
     
     
         19 . A method in accordance with  claim 12 , wherein providing the microorganism includes selecting the microorganism with an increased capacity to produce acetolactate. 
     
     
         20 . A method in accordance with  claim 12 , wherein the microorganism is an engineered  S. cerevisiae  yeast.