Regulation of alcohol fermentation by Escherichia coli
The purpose of this project is to elucidate the way in which the fermentative synthesis of ethanol is regulated in the facultative anaerobe Escherichia coli. Focus is on the two final steps in alcohol synthesis, which are catalyzed by alcohol dehydrogenase and acetaldehyde CoA dehydrogenase. We have isolated a series of mutations affecting the expression of these enzymes. Some of these mutations are in the structural genes for these enzymes; others affect the regulation of the adh operon. We have recently cloned the genes coding for these enzymes and are now studying the effect of multiple copies of the adh gene on fermentative growth and its regulation. A recently invented technique, proton suicide has allowed the selection of a variety of novel mutants affecting fermentation which are presently being characterized. We have isolated a comprehensive collection of operon fusions in which the lacZ structural gene is fused to promoters that are inactive aerobically but active anaerobically. Although these genes (like adh) are only expressed under anaerobic conditions, the level of induction varies from two-fold to nearly 100-fold. The nitrogen source, medium pH, nature of the buffer, presence of alternative electron acceptors (e.g., nitrate), and other factors exert a great effect on the expression of many of these genes. In the near future we will investigate control mechanisms common to the adh operon and other anaerobically regulated genes.
- Research Organization:
- Southern Illinois Univ., Carbondale (USA). Dept. of Microbiology
- DOE Contract Number:
- AC02-82ER12095
- OSTI ID:
- 6058481
- Report Number(s):
- DOE/ER/12095-T1; ON: DE86009055
- Country of Publication:
- United States
- Language:
- English
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Regulation of alcohol fermentation by Escherichia coli. Progress report, July 1989--June 1990
Regulation of alcohol fermentation by Escherichia coli
Related Subjects
09 BIOMASS FUELS
ALCOHOL DEHYDROGENASE
GENE OPERONS
GENE REGULATION
ESCHERICHIA COLI
GENETIC ENGINEERING
GENE MUTATIONS
DNA-CLONING
ENZYME INDUCTION
FRACTIONATION
GENE AMPLIFICATION
BACTERIA
CLONING
ENZYMES
HEMIACETAL DEHYDROGENASES
MICROORGANISMS
MUTATIONS
OXIDOREDUCTASES
SEPARATION PROCESSES
550200* - Biochemistry
550700 - Microbiology
090222 - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989)