Pentose fermentation by recombinant zymomonas
First Claim
1. A process for producing ethanol comprising:
- providing a feedstock containing arabinose, adding the microorganism Zymomonas mobilis to the feedstock, said microorganism containing exogenous genes that encode L-arabinose isomerase, L-ribulokinase and L-ribulose-5-phosphate-4-epimerase, transaldolase and transketolase which impart arabinose to ethanol fermentation capability and wherein said microorganism without said genes is incapable of fermenting said arabinose to ethanol,allowing the microorganism to ferment the arabinose in the feedstock to ethanol, and separating the ethanol.
2 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to microorganisms which normally do not ferment pentose sugar and which are genetically altered to ferment pentose sugar to produce ethanol, and fermentation processes utilizing the same. Examples include Zymomonas mobilis which has been transformed with combinations of E. coli genes for xylose isomerase, xylulokinase, transaldolase, transketolase, L-arabinose isomerase, L-ribulokinase, and L-ribulose 5-phosphate 4-epimerase. Expression of the added genes are under the control of Zymomonas mobilis promoters. These newly created microorganisms are useful for fermenting pentoses and glucose, produced by hydrolysis of hemicellulose and cellulose, to produce ethanol.
-
Citations
10 Claims
-
1. A process for producing ethanol comprising:
- providing a feedstock containing arabinose, adding the microorganism Zymomonas mobilis to the feedstock, said microorganism containing exogenous genes that encode L-arabinose isomerase, L-ribulokinase and L-ribulose-5-phosphate-4-epimerase, transaldolase and transketolase which impart arabinose to ethanol fermentation capability and wherein said microorganism without said genes is incapable of fermenting said arabinose to ethanol,
allowing the microorganism to ferment the arabinose in the feedstock to ethanol, and separating the ethanol. - View Dependent Claims (3, 4, 5)
- providing a feedstock containing arabinose, adding the microorganism Zymomonas mobilis to the feedstock, said microorganism containing exogenous genes that encode L-arabinose isomerase, L-ribulokinase and L-ribulose-5-phosphate-4-epimerase, transaldolase and transketolase which impart arabinose to ethanol fermentation capability and wherein said microorganism without said genes is incapable of fermenting said arabinose to ethanol,
-
2. A process for producing ethanol comprising:
- providing a feedstock containing xylose, adding the microorganism Zymomonas mobilis to the feedstock, said microorganism containing exogenous genes that encode xylose isomerase, xylulokinase, transaldolase and transketolase and capable of growing on xylose as a sole carbon source and fermenting said xylose to ethanol at about 88% of theoretical yield and wherein said microorganism without said genes is incapable of growing on or fermenting said xylose in the feedstock to ethanol, allowing the microorganism to ferment the xylose in the feedstock to ethanol, and separating the ethanol.
- View Dependent Claims (8, 9, 10)
-
6. A process for producing ethanol comprising, providing a mixed sugar feedstock consisting essentially of at least two sugars selected from the group consisting of glucose, fructose, sucrose, xylose and arabinose, adding the microorganism Zymomonas mobilis containing exogenous genes to the feedstock, allowing the fermentation to ethanol from sugar contained in the feedstock to occur, and separating the ethanol, wherein the microorganism is Zymomonas mobilis containing exogenous genes from a microorganism selected from the group consisting of:
- E. coli, Xanthomonas, Klebsiella, Rhodobacter, Flavobacterium, Acetobacter, Gluconobacter, Rhizobium, Agrobacterium, Salmonella and Pseudomonads which encode L-arabinose isomerase, L-ribulokinase, L-ribulose 5-phosphate 4-epimerase, transaldolase and transketolase, and/or Zymomonas mobilis containing exogenous genes from a microorganism selected from the group consisting of E. coli, Xanthomonas, Klebsiella, Rhodobacter, Flavobacterium, Acetobacter, Gluconobacter, Rhizobium, Agrobacterium, Salmonella and Pseudomonads which encode xylose isomerase, xylulokinase, transaldolase and transketolase, wherein the microorganism is capable of growing on xylose as a sole carbon source and fermenting said xylose to ethanol at about 88% of theoretical yield.
- View Dependent Claims (7)
Specification