Clostridium Acetobutylicum
Mostrando 13-24 de 185 artigos, teses e dissertações.
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13. Bacteriocin production by Clostridium acetobutylicum in an industrial fermentation process.
High titers of a noninducible bacteriocin were produced by Clostridium acetobutylicum in a molasses fermentation medium used for the industrial production of solvents. Release of the bacteriocin towards the end of the exponential growth phase was accompanied by lysis of the culture and inhibition of the production of solvents. The producer cells were sensiti
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14. Production of Heterologous and Chimeric Scaffoldins by Clostridium acetobutylicum ATCC 824
Clostridium acetobutylicum ATCC 824 converts sugars and various polysaccharides into acids and solvents. This bacterium, however, is unable to utilize cellulosic substrates, since it is able to secrete very small amounts of cellulosomes. To promote the utilization of crystalline cellulose, the strategy we chose aims at producing heterologous minicellulosomes
American Society for Microbiology.
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15. Physical and genetic map of the Clostridium acetobutylicum ATCC 824 chromosome.
A physical and genetic map of the Clostridium acetobutylicum ATCC 824 chromosome was constructed. The macrorestriction map for CeuI, EagI, and SstII was created by ordering the 38 restriction sites by one- and two-dimensional pulsed-field gel electrophoresis (PFGE) and by using an original strategy based on the CeuI enzyme and indirect end labelling by hybri
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16. Isolation and characterization of Clostridium acetobutylicum mutants with enhanced amylolytic activity.
Clostridium acetobutylicum mutants BA 101 (hyperamylolytic) and BA 105 (catabolite depressed) were isolated by using N-methyl-N'-nitro-N-nitrosoguanidine together with selective enrichment on the glucose analog 2-deoxyglucose. Amylolytic enzyme production by C. acetobutylicum BA 101 was 1.8- and 2.5-fold higher than that of the ATCC 824 strain grown in starc
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17. Structure of an endo-beta-1,4-glucanase gene from Clostridium acetobutylicum P262 showing homology with endoglucanase genes from Bacillus spp.
The nucleotide sequence of an endo-beta-1,4-glucanase gene of Clostridium acetobutylicum contained two putative extended promoter consensus sequences, a Shine-Dalgarno sequence and a TTG initiation codon. The nucleotide sequence of the gene coding for the C-terminal region of this enzyme was not required for activity. Extensive homology in the nucleotide and
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18. Carboxymethyl cellulase and cellobiase production by Clostridium acetobutylicum in an industrial fermentation medium.
The production of a carboxymethyl cellulase and a cellobiase by Clostridium acetobutylicum was demonstrated. In liquid medium the carboxymethyl cellulase was induced by molasses, and it was not repressed by glucose. Optimum carboxymethyl cellulase activity occurred at pH 4.6 and 37 degrees C.
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19. Regulation and localization of amylolytic enzymes in Clostridium acetobutylicum ATCC 824.
Amylolytic activity was primarily cell associated when Clostridium acetobutylicum was grown on glucose or maltose and primarily extracellular when grown on dextrin or starch. Total amylolytic activity decreased with increasing glucose concentration. When this microorganism was grown in P2 medium containing starch, the intracellular amylolytic activity was 90
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20. Sporulation of Clostridium acetobutylicum P262 in a Defined Medium
A defined minimal sporulation medium for Clostridium acetobutylicum P262, which produces high levels of solvents, is described. The overall sporulation sequence was similar to that of other endospore-forming bacteria. However, we observed a presporulation stage, during which swollen phase-bright cells which contained large amounts of granulose formed. During
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21. Characterization, Biosynthesis, and Regulation of Granulose in Clostridium acetobutylicum
Synthesis of granulose was investigated in 15 solvent-producing Clostridium strains. Only one of the strains did not produce granulose. The structure of granulose in Clostridium acetobutylicum P262 consisted of a high-molecular-weight polyglucan containing only (1→4) linked d-glucopyranose units. Biosynthesis of granulose in C. acetobutylicum P262 was depe
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22. Direct Selection of Clostridium acetobutylicum Fermentation Mutants by a Proton Suicide Method
Clostridium acetobutylicum ATCC 10132 mutants altered in acetic acid synthesis or in the shift to solventogenesis were directly selected by a proton suicide method after mutagenic treatment, by using bromide and bromate as selective agents. The mutants were characterized according to their solvent and acid production. On the selection plates they differed in
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23. Transmembrane pH of Clostridium acetobutylicum is inverted (more acidic inside) when the in vivo activity of hydrogenase is decreased.
Evidence is reported here that alkalinization of Clostridium acetobutylicum cytoplasm involves hydrogenase activity. A decrease of in vivo hydrogenase activity is accompanied by intracellular accumulation of protons leading to a negative (interior acidic) pH gradient. However, the organism is able to maintain a constant proton motive force by interconverting
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24. Isolation and characterization of butanol-resistant mutants of Clostridium acetobutylicum.
In a wild-type strain of Clostridium acetobutylicum isolated from soil, solvent production appeared limited by butanol toxicity. Butanol-resistant mutants have been obtained which produced significantly higher solvent concentrations (about 30%) than the wild-type strain. Some other physiological differences were observed between a selected resistant mutant a