1. Thomas W. Jeffries, Director of Institute for Microbial and Biochemical Technology, USDA
Microorganism: Pichia stipitis
Description of research: Xylose fermentation; Metabolic regulation; Metabolic engineering; Yeast genetics; Depolymerization of cellulosic and hemicellulosic polysaccharides; Lignin biodegradation; Bioprocess engineering; Microbial strain selection and development; Regulation of heterologous enzymes; Overproduction of primary and secondary metabolites; Overproduction of extracellular enzymes; Microbial physiology.
Novozymes used the strain provided by Thomas Jeffries to ferment the mixture of glucose and xylose.
2. Nancy W. Y. Ho, Research Molecular Biologist/Group Leader, Laboratory of Renewable Resources Engineering, Purdue University
Microorganism: Saccharomyces cerevisiae 259ST. A genetically modified version of 259A capable of xylose fermentation due to insertion of xylose reductase and xylitol dehydrogenase genes from P. stipitis and overexpression of xylulokinase.
Iogen used the engineered yeast developed by Dr. Ho to produce ethanol from wheat straw.UBC and Tembec Chemicals Products have tested 259ST yeast on fermenting spent sulfite pulping liquor (SSL).
3. Lonnie O. Ingram ,Distinguished Professor, Director, Florida Center for Renewable Chemicals and Fuels (FCRC),Department of Microbiology and Cell Science University of Florida.
Microorganism: Escherichia coli
General areas: Global redirection of central metabolism by genetic engineering; Industrial fermentation processes; Carbohydrate metabolism; Expression and secretion of glycohydrolases which degrade plant polymers; Alcohol tolerance
4. Lisbeth Olsson, Professor, DTU Biosys, Department of Systems Biology,Technical University of Denmark, Center for Microbial Biotechnology, BioCentrum-DTU
Microorganism: Saccharomyces cerevisiae strains (F12, CR4, and CB4)
Article abstract: Fermentations with three different xylose-utilizing recombinant Saccharomyces cerevisiae strains (F12, CR4, and CB4) were performed using two different wheat hemicellulose substrates, unfermented starch free fibers, and an industrial ethanol fermentation residue, vinasse. With CR4 and F12, the maximum ethanol concentrations obtained were 4.3 and 4 g/L, respectively, but F12 converted xylose 15% faster than CR4 during the first 24 h. The comparison of separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) with F12 showed that the highest, maximum ethanol concentrations were obtained with SSF. In general, the volumetric ethanol productivity was initially, highest in the SHF, but the overall volumetric ethanol productivity ended up being maximal in the SSF, at 0.013 and 0.010 g/L.h, with starch free fibers and vinasse, respectively.
"Separate and Simultaneous enzymatic hydrolysis and fermentation of wheat hemicellulose with recombinant xylose utilizing Saccharomyces cerevisiae", Applied Biochemistry and Biotechnology, vol: 129-132, pages: 117-129, 2006
5. Taso, George, Laboratory of Renewable Resources Engineering, A. A. Potter Engineering Center, Purdue University
Microorganism: First using xylose isomerase and then yeast.
Article abstract:d-Xylulose, an intermediate of d-xylose catabolism, was observed to be fermentable to ethanol and carbon dioxide in a yield of greater than 80% by yeasts (including industrial bakers' yeast) under fermentative conditions. This conversion appears to be carried out by many types of yeast known for d-glucose fermentation. In some yeasts, xylitol, in addition to ethanol, was produced from d-xylulose. Fermenting yeasts are also able to produce ethanol from d-xylose when d-xylose isomerizing enzyme is present. The results indicate that ethanol could be produced from d-xylose in a yield of greater than 80% by a two-step process. First, d-xylose is converted to d-xylulose by xylose isomerase. d-Xylulose is then fermented to ethanol by yeasts.
5. Taso, George, Laboratory of Renewable Resources Engineering, A. A. Potter Engineering Center, Purdue University
Microorganism: First using xylose isomerase and then yeast.
Article abstract:d-Xylulose, an intermediate of d-xylose catabolism, was observed to be fermentable to ethanol and carbon dioxide in a yield of greater than 80% by yeasts (including industrial bakers' yeast) under fermentative conditions. This conversion appears to be carried out by many types of yeast known for d-glucose fermentation. In some yeasts, xylitol, in addition to ethanol, was produced from d-xylulose. Fermenting yeasts are also able to produce ethanol from d-xylose when d-xylose isomerizing enzyme is present. The results indicate that ethanol could be produced from d-xylose in a yield of greater than 80% by a two-step process. First, d-xylose is converted to d-xylulose by xylose isomerase. d-Xylulose is then fermented to ethanol by yeasts.
"Production of Ethanol from d-Xylose by Using d-Xylose Isomerase and Yeasts", Appl Environ Microbiol. 1981 February; 41(2): 430–436.
6. Ronald Hector, Stephen Hughes and Xin Liang-Li, the research molecular biologists with the USDA's Agricultural Research Service.
Research: Optimizations of genes of commercial yeasts for production of fuel ethanol from hemicellulosic biomass are carried out to meet the rapidly expanding need for ethanol. These yeast strains will be used in cellulosic ethanol production.
7. Richard Bolin
US patent: 5372939: Combined enzyme: Schizosaccharoyces pombe, cellulase, .beta.-glucosidase, and xylose isomerase
8. Iogen, Recombinant yeasts (424A). The yeast strain was provided by Dr. Nancy Ho in Purdue University.
9. Xethanol, proceeding with a Cooperative Research and Development Agreeement (CRADA) with FPL to engineer genetically modified yeasts that will substantially increase fermentation time of such feedstocks such as xylose, to produce either ethanol or xylitol, a natural sweetener.
10. Lee R. Lynd, Chemical and Biochemical Engineering Program, Dartmouth College and CFO of Mascoma
Microorganism: Thermoanaerobacter thermosaccharolyticum HG-8.
Study the xylose-utilizing thermophiles, Thermoanaerobacterium saccharolyticum and Thermoanaerobacterium thermosaccharolyticum.
Mascoma’s research laboratories are now developing a new generation of microbes and processes for economical conversion of cellulosic feedstocks into ethanol.
11. Min Zhang, National Renewable Energy Laboratory, Applied Biological Sciences
Microorganism: Bacterium Zymomonas mobilis
The ethanol-producing bacterium Zymomonas mobilis was metabolically engineered to broaden its range of fermentable substrates to include the pentose sugar xylose. Two operons encoding xylose assimilation and pentose phosphate pathway enzymes were constructed and transformed into Z. mobilis in order to generate a strain that grew on xylose and efficiently fermented it to ethanol. This strain efficiently fermented both glucose and xylose, which is essential for economical conversion of lignocellulosic biomass to ethanol.
Metabolic Engineering of a Pentose Metabolism Pathway in Ethnologenic Z Mobilis. Science Vol. 267. 1995, pp. 240 - 243
12. VTT Technical Research Centre
Microorganism: Saccharomyces cerevisiae
They have studied recombinant Saccharomyces cerevisiae yeast metabolically engineered to utilise the pentose sugar xylose, and compared the gene expression profiles on xylose to glucose-metabolizing cells.
13. Jeffrey Tolan and R. K. Finn, School of Chemical Engineering, Cornell University
Microorganism: Erwinia chrysathemi
Fermentation of D-xylose and L-arabinose to ethanol by Erwinia chrysathemi, Appl. Envirom. Microbiol., 53(9): 2033-2038, 1987.
14. Alexander, M.A.; Chapman, T.W.;& Jeffries, T.W. Department of Chem. Eng. University of Wisconsin
Microorganism: Candida shehatae
Continuous xylose ferrmentation by Candida shehatae in a two-stage reactor. Applied biochemistry and biotechnology, v. 17:221-229, 1988
15. Satoshi Katahira1, Atsuko Mizuike, Hideki Fukuda1 and Akihiko Kondo, Department of Chemical Science and Engineering, Faculty of Engineering, Kobe University,
Microorganism: Recombinant yeast strain
Ethanol fermentation from lignocellulosic hydrolysate by a recombinant xylose- and cellooligosaccharide-assimilating yeast strain. Applied Microbiology and biotechnology, v. 72(6):1136-1143, 2006
16. Yong-su Jin, University of Illinois
Microorganism: E. coli
Improvement of xylose fermentation by recombinant Saccharomycescerevisiae through systematic and combinatorial approaches is funded by EBI (Energy Biosciences Institute). EBI is a new research organization that will pursue basic and applied research in the area of cellulosic biofuels, enhanced oil recovery, microbially-enhanced fossil fuel processing and biosequestration.
17. Girishchandra Patel, Division of Biological Sciences,National research council of Canada
Microorganism: Bacteroides polypragmatus
Fermentation of xylose and hemicellulose hydrolysates by an ethanol-adapted culture of Bacteroides polypragmatus, Archives of Microbiology, 146(1):68-73, 1986
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