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Title: 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 effectmore » 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.« less
Authors:
Publication Date:
OSTI Identifier:
6058481
Report Number(s):
DOE/ER/12095-T1
ON: DE86009055
DOE Contract Number:
AC02-82ER12095
Resource Type:
Technical Report
Research Org:
Southern Illinois Univ., Carbondale (USA). Dept. of Microbiology
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 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)