Glycolytic flux in Zymomonas mobilis: enzyme and metabolite levels during batch fermentation
The rate at which Z. mobilis (Entner-Doudoroff pathway) converts high concentrations of glucose (20%) into ethanol plus CO/sub 2/ changes as ethanol accumulates in the surrounding broth. This decline in glycolytic activity (per milligram of cell protein) does not result from inhibitory effects of ethanol, which can be reversed immediately by ethanol removal. The peak of fermentative activity (58 ..mu..mol of CO/sub 2/ evolved per mg of cell protein per h) occurred after the accumulation of 1.1% ethanol (18 h) and declined to one-half this rate after 30 h (6.2% accumulated ethanol), although the cell number continued to increase. These times corresponded to the end of exponential growth and to the onset of the stationary phase (on the basis of measurement of cell protein), respectively. An examination of many of the requirements for fermentation revealed three possible reasons for this early decline in activity: decreased abundance of nucleotides, a decrease in internal pH from 6.3 to 5.3, and a decrease in the specific activities of two glycolytic enzymes (pyruvate kinase and glyceraldehyde-3-phosphate dehydrogenase).
- Research Organization:
- Univ. of Florida, Gainesville
- OSTI ID:
- 6105405
- Journal Information:
- J. Bacteriol.; (United States), Vol. 169:8
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ethanol production during batch fermentation with Saccharomyces cerevisiae: changes in glycolytic enzymes and internal pH
Ethanologenic Enzymes of Zymomonas mobilis
Related Subjects
ETHANOL
BIOSYNTHESIS
GLUCOSE
FERMENTATION
OXIDOREDUCTASES
ENZYME ACTIVITY
PHOSPHOTRANSFERASES
ZYMOMONAS MOBILIS
METABOLISM
BATCH CULTURE
BIOLOGICAL PATHWAYS
GLYCOLYSIS
TOXICITY
ALCOHOLS
ALDEHYDES
BACTERIA
BIOCONVERSION
CARBOHYDRATES
ENZYMES
HEXOSES
HYDROXY COMPOUNDS
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
SACCHARIDES
SYNTHESIS
TRANSFERASES
090222* - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989)
140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)