Metabolic engineering of Clostridium acetobutylicum ATCC 824 for increased solvent production by enhancement of acetone formation enzyme activities using a synthetic acetone operon
- Northwestern Univ., Evanston, IL (United States). Dept. of Chemical Engineering
- Rice Univ., Houston, TX (United States)
The ability to genetically alter the product-formation capabilities of Clostridium acetobutylicum is necessary for continued progress toward industrial production of the solvents, butanol and acetone, by fermentation. Batch fermentations at pH 4.5, 5.5, or 6.5 were conducted using C. acetobutylicum ATCC 824 (pFNK6). Plasmid pFNK6 contains a synthetic operon (the ace operon'') in which the three homologous acetone-formation genes (adc, ctfA, and ctfB) are transcribed from the adc promoter. The corresponding enzymes (acetoacetate decarboxylase and CoA-transferase) were best expressed in pH 4.5 fermentations. However, the highest levels of solvents were attained at pH 5.5. Relative to the plasmid-free control strain at pH 5.5, ATCC 824 (pFNK6) produced 95%, 37%, and 90% higher final concentrations of acetone, butanol, and ethanol, respectively; a 50% higher yield (g/g) of solvents on glucose; and a 22-fold lower mass of residual carboxylic acids. At all pH values, the acetone-formation enzymes were expressed earlier with ATCC 824 (pFNK6) than in control fermentations, leading to earlier induction of acetone formation.
- OSTI ID:
- 5891282
- Journal Information:
- Biotechnology and Bioengineering; (United States), Vol. 42:9; ISSN 0006-3592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ACETONE
BIOSYNTHESIS
BUTANOLS
CLOSTRIDIUM ACETOBUTYLICUM
GENETIC ENGINEERING
DECARBOXYLASES
ENZYME ACTIVITY
ETHANOL
TRANSFERASES
FERMENTATION
GENE OPERONS
GLUCOSE
ALCOHOLS
ALDEHYDES
BACTERIA
BIOCONVERSION
BIOTECHNOLOGY
CARBOHYDRATES
CARBON-CARBON LYASES
CARBOXY-LYASES
CLOSTRIDIUM
ENZYMES
HEXOSES
HYDROXY COMPOUNDS
KETONES
LYASES
METHANOGENIC BACTERIA
MICROORGANISMS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PROTEINS
SACCHARIDES
SYNTHESIS
090900* - Biomass Fuels- Processing- (1990-)
550200 - Biochemistry