Methods and compositions for butanol production
A butanol producing cell and a method for the production of butanol are provided. Butanol producing cells comprising a butanol synthesis system or butanol export proteins may be used to enhance the production of butanol from a carbon substrate composition.
1. An isolated butanol-producing microbial cell comprising a heterologous nucleic acid encoding a multi-drug resistance protein selected from the group consisting of OmrA and LmrA.
2. The microbial cell of claim 1 , wherein the cell is resistant to butanol-associated toxicity.
3. The microbial cell of claim 1 , wherein the cell further comprises a nucleic acid encoding a polypeptide that catalyzes a substrate to product conversion selected from the group consisting of:
(a) acetyl-CoA to acetoacetyl-CoA;
(b) acetoacetyl-CoA to 3-hydroxybutyryl-CoA;
(c) 3-hydroxybutyryl-CoA to crotonyl-CoA;
(d) crotonyl-CoA to butyryl-CoA;
(e) butyryl-CoA to butyraldehyde; and
(f) butyraldehyde to 1-butanol.
4. The microbial cell of claim 3 , wherein the nucleic acid encoding a polypeptide that catalyzes a substrate to product conversion is heterologous to the microbial host cell.
5. The microbial cell of claim 1 , wherein the cell is selected from the group consisting of Clostridium beijerinckii and Clostridium acetobutylicum .
6. An isolated butanol-producing microbial cell comprising a heterologous nucleic acid encoding a polypeptide that catalyzes a substrate to product conversion selected from the group consisting of:
(a) acetyl-CoA to acetoacetyl-CoA;
(b) acetoacetyl-CoA to 3-hydroxybutyryl-CoA;
(c) 3-hydroxybutyryl-CoA to crotonyl-CoA;
(d) crotonyl-CoA to butyryl-CoA;
(e) butyryl-CoA to butyraldehyde; and
(f) butyraldehyde to 1-butanol, wherein the microbial cell is selected from the group consisting of Qenococcus Qeni and Lactococcus lactis.
7. The microbial cell of claim 6 , wherein the cell is resistant to butanol-associated toxicity.
8. An isolated butanol-resistant microbial cell, wherein the cell is ATCC No. PTA 8515.
9. The isolated butanol-resistant microbial cell of claim 7 , wherein the cell comprises a heterologous nucleic acid encoding a polypeptide that exports butanol.
10. A method for increasing butanol production in a microbial cell comprising:
(a) providing a microbial cell selected from any one of claims 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 or 9 ; and
(b) contacting the microbial host cell with a carbon substrate.
11. The method of claim 10 , wherein the microbial cell is characterized by increased resistance to butanol.
12. The method of claim 10 , wherein the carbon substrate is a fermentable carbon substrate.
13. The method of claim 12 , wherein the fermentable carbon substrate is selected from the group consisting of potato, potato waste, sulfite waste liquor, sugar beet, wheat, rye, oats, CO 2 , distillers dry grain solids (DDGS), corn, soy molasses, whey permeate, Jerusalem artichokes, corn fiber, and molasses.