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US 12,662,687 B2Granted
Methods and compositions for the production of xylitol from xylose utilizing dynamic metabolic control
AssigneeDuke University
InventorsMichael David Lynch, Shuai Li
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Abstract
The present disclosure is related to genetically engineered microbial strains and related bioprocesses for the production of xylitol. Specifically, the use of dynamically controlled synthetic metabolic valves to reduce the activity of certain enzymes, leads to increased xylitol production in a two-stage process.
Claims22
A genetically modified E. coli microorganism for producing xylitol from xylose comprising:
- a first gene expression-silencing synthetic metabolic valve or an enzymatic degradation synthetic metabolic valve for overexpression of xylose reductase in a productive stationary phase;
- a second gene modification comprising chromosomal modification of the xylA gene to provide for reducing the amount of xylose isomerase enzyme in a productive stationary phase;
- and
- further comprising a gene-silencing synthetic metabolic valve or the enzyme degradation synthetic metabolic valve are directed to control of the gene encoding enoyl-ACP reductase, or the enoyl-ACP reductase enzyme in a productive stationary phase,
- wherein the genetically modified E. coli microorganism will produce xylitol in a biofermentation process comprising growing the genetically modified E. coli microorganism in a medium in a growth phase, transitioning to a productive stationary phase, the transition comprising:
- slowing or stopping microorganism growth, inducing the first gene modification, to effect overexpression of xylose reductase and the second gene expression-silencing synthetic metabolic valve or an enzymatic degradation synthetic metabolic valve to decrease the total amount of xylose isomerase enzyme activity, and producing xylitol in the productive stationary phase,
- wherein the biofermentation process occurs in a media in which xylose was substituted for glucose, 1 gram xylose for 1 gram glucose.
4 more elements
A genetically modified E. coli microorganism for producing xylitol from xylose comprising:
- a first gene expression-silencing synthetic metabolic valve or an enzymatic degradation synthetic metabolic valve for overexpression of xylose reductase in a productive stationary phase;
- a second gene modification comprising chromosomal modification of the xylA gene to provide for reducing the amount of xylose isomerase enzyme in a productive stationary phase and
- wherein the genetically modified E. coli microorganism will produce xylitol in a biofermentation process comprising growing the genetically modified E. coli microorganism in a medium in a growth phase, transitioning to a productive stationary phase, the transition comprising:
- slowing or stopping microorganism growth, inducing the first gene modification, to effect overexpression of xylose reductase and the second gene expression silencing synthetic metabolic valve or an enzymatic degradation synthetic metabolic valve to decrease the total amount of xylose isomerase enzyme activity, and producing xylitol in the productive stationary phase,
- wherein the biofermentation process occurs in a media in which xylose was substituted for glucose, 1 gram xylose for 1 gram glucose.
2 more elements
Dependencies are inferred from the claim text.