Microorganisms that co-consume glucose with non-glucose carbohydrates and methods of use
Microorganisms that co-consume glucose with non-glucose carbohydrates, such as xylose, and methods of using same. The microorganisms comprise modifications that reduce or ablate the activity of a phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) protein or modifications that reduce or ablate the activity of a phosphoglucose isomerase and a GntR. The PTS protein may be selected from an enzyme I (EI), an HPr, an FPr, and an enzyme II Glc (EII Glc ). Additional modifications include reduction or ablation of the activity of a pyruvate formate lyase, a lactate dehydrogenase, and a fumarate reductase and inclusion of recombinant pyruvate decarboxylase and alcohol dehydrogenase genes. The microorganisms are particularly suited to co-consuming glucose and xylose in media containing these substrates and producing ethanol therefrom.
1. A recombinant microorganism comprising:
a genetic modification that reduces or ablates the activity of a phosphoglucose isomerase;
a genetic modification that reduces or ablates the activity of a GntR; and
one or more of:
a genetic modification that reduces or ablates the activity of a pyruvate formate lyase; and
a recombinant pyruvate decarboxylase gene.
2. The recombinant microorganism of claim 1 wherein the microorganism is a bacterium.
3. The recombinant microorganism of claim 1 comprising a genetic modification that reduces or ablates the activity of a pyruvate formate lyase.
4. The recombinant microorganism of claim 1 further comprising a genetic modification that reduces or ablates the activity of a lactate dehydrogenase.
5. The recombinant microorganism of claim 1 comprising a recombinant pyruvate decarboxylase gene and further comprising a recombinant alcohol dehydrogenase gene.
6. The recombinant microorganism of claim 1 further comprising one or more of:
a genetic modification that reduces or ablates the activity of a lactate dehydrogenase; and
a recombinant alcohol dehydrogenase gene.
7. The recombinant microorganism of claim 1 comprising:
a genetic modification that reduces or ablates the activity of a pyruvate formate lyase;
a genetic modification that reduces or ablates the activity of a lactate dehydrogenase;
a recombinant pyruvate decarboxylase gene; and
a recombinant alcohol dehydrogenase gene.
8. A method of consuming a carbohydrate comprising culturing the recombinant microorganism of claim 1 in a medium comprising the carbohydrate, wherein the microorganism consumes the carbohydrate during the culturing.
9. The method of claim 8 wherein the medium comprises glucose and xylose.
10. The method of claim 9 wherein the microorganism consumes at least about 10% of an initial amount of the xylose in the medium during the time the microorganism consumes about 20% of an initial amount of the glucose in the medium.
11. The method of claim 8 wherein the medium comprises a biomass hydrolysate.
12. The method of claim 11 wherein the biomass hydrolysate is an enzymatic hydrolysate, an acid hydrolysate, or a hydrolysate of an ionic liquid.
13. The method of claim 8 wherein the microorganism is adapted to growth in a first medium comprising a component selected from the group consisting of glucose, xylose, and ethanol prior to culturing the microorganism in the medium.
14. The method of claim 8 wherein the culturing produces at least about 300 mM ethanol.
15. The recombinant microorganism of claim 1 further comprising a recombinant alcohol dehydrogenase gene.
16. The recombinant microorganism of claim 1 comprising a recombinant pyruvate decarboxylase gene.