Construction of an Escherichia coli K-12 mutant for homoethanologenic fermentation of glucose or xylose without foreign genes.
Conversion of lignocellulosic feedstocks to ethanol requires microorganisms that effectively ferment both hexose and pentose sugars. Towards this goal, recombinant organisms have been developed in which heterologous genes were added to platform organisms such as Saccharomyces cerevisiae, Zymomonas mobilis, and Escherichia coli. Using a novel approach that relies only on native enzymes, we have developed a homoethanologenic alternative, Escherichia coli strain SE2378. This mutant ferments glucose or xylose to ethanol with a yield of 82% under anaerobic conditions. An essential mutation in this mutant was mapped within the pdh operon (pdhR aceEF lpd), which encodes components of the pyruvate dehydrogenase complex. Anaerobic ethanol production by this mutant is apparently the result of a novel pathway that combines the activities of pyruvate dehydrogenase (typically active during aerobic, oxidative metabolism) with the fermentative alcohol dehydrogenase.
Kim
Youngnyun
Y
Department of Microbiology and Cell Science, Box 110700, University of Florida, Gainesville, FL 32611, USA.
Ingram
L O
LO
Shanmugam
K T
KT
D000693:Anaerobiosis; D048168:Escherichia coli K12 / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D008954:Models, Biological; D009154:Mutation; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics; D012441:Saccharomyces cerevisiae; D014994:Xylose / Q000378:metabolism*
D029968:Escherichia coli Proteins; D011768:Pyruvate Dehydrogenase Complex; D000431:Ethanol; D014994:Xylose; D005947:Glucose