Conversion of cellulose to ethanol by mesophilic bacteria: Final report, July 15, 1984-November 14, 1987
The physiology and genetics of mesophilic cellulose-fermenting, ethanol-producing bacteria were investigated in order to develop strains of bacteria that can be used in the conversion of biomass materials to ethanol. Studies involved, primarily, a species of Clostridium (strain C7) isolated from the sediment of a freshwater swamp. A cellulose-fermenting bacterium from wetwood and several strains of nitrogen-fixing cellulose-fermenting bacteria from soil were also investigated. As a first step to understanding the genetic organization of the cellulase system of these bacteria, enzymes associated with the hydrolysis of cellulosic materials by strain C7 were characterized. Crystalline cellulose was solubilized by a 700,000 molecular weight complex comprised of approximately 18 polypeptides. This complex was required in its entirety to degrade crystalline cellulose, inasmuch as this activity was lost when the complex was disrupted into its constituent proteins. Studies involving a cellulase-deficient mutant supported this conclusion. Other enzymes that were investigated included ..beta..-glucosidase and cellobiose phosphorylase. Also, a strain C7 gene encoding ..beta..-xylosidase was cloned in E. coli. Enzyme purified from E. coli cells containing the cloned clostridial gene had a molecular weight of 240,000. A bacteriophage of strain C7 was isolated and characterized, and methods for forming protoplasts and regenerating cell walls of strain C7 were developed. 10 refs.
- Research Organization:
- Massachusetts Univ., Amherst (USA)
- DOE Contract Number:
- AC02-81ER10878
- OSTI ID:
- 5532269
- Report Number(s):
- DOE/ER/10878-T4; ON: DE88006017
- Country of Publication:
- United States
- Language:
- English
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550200 -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
CELLULASE
CELLULOLYTIC ACTIVITY
CHROMATOGRAPHY
CLONING
CLOSTRIDIUM
DNA-CLONING
DOCUMENT TYPES
ELECTROPHORESIS
ENZYME ACTIVITY
ENZYMES
FRACTIONATION
GEL PERMEATION CHROMATOGRAPHY
GLUCOSIDASE
GLYCOSYL HYDROLASES
HYDROLASES
MICROORGANISMS
NITROGEN FIXATION
O-GLYCOSYL HYDROLASES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PROGRESS REPORT
SEPARATION PROCESSES
TRANSFERASES