جستجوی مقالات مرتبط با کلیدواژه « clostridium acetobutylicum » در نشریات گروه « زیست شناسی »

Butanol is a fuel blended more readily with gasoline and hydrocarbon products and contains higher heat value in comparison with ethanol. Clostridium acetobutylicum is able to produce considerable amount of butanol. Acetone and ethanol are other products of this strain. Simple models describing the production of these metabolites like Monod model are restricted to prognosticate intracellular processes. The mathematical expression of intracellular metabolites production is applied to optimize the production of the desired compound, especially, in metabolic engineering. In this study, the structured model of the metabolic pathway of Clostridium acetobutylicum was utilized to describe and to predict the dynamical variations of intracellular and extracellular metabolites. Mathematical equations were solved by SimBiology and results were compared with experimental data published in literature, which revealed an appropriate conformity. The effect of butyrate and acetate on the butanol production was investigated and results demonstrated the butanol production enhancement in the presence of these substances in the culture media. The butyrate presence in the media led to both increase of butanol concentration and decrease of time required to attain the maximum butanol production. The butanol concentration were 120.48 and 138.35 mM when the initial concentrations of acetate and butyrate were 100 and 0 mM, and 0 and 100 mM respectively .Due to the irreversible production reaction of acetone in the metabolic pathway, butanol production was not influenced by the acetone concentration, but its elimination from the cell pathway increased the butanol production.

Greenhouse effect problems، environmental pollution، global increase in oil demand، and reduced fossil fuel resources have boosted research on the production of renewable energies such as bioenegries in recent years. Amongst various biofuels، biobutanol has been recently introduced as a replacement liquid fuel for gasoline and gas oil. Anaerobic bacteria such as Clostridium acetobutylicum are able to produce acetone، butanol، and ethanol using different sugar sources. This bacterium exhibits amylolytic activity and therefore is able to hydrolyzes starch to glucose and use it directly as carbon source. In this study، three substrates including glucose، treated starch and starch were used in different concentrations to produce butanol by Clostridium acetobutylicum PTCC 1492. For all three carbon sources، 60 g/ l of substrate was found as the optimum concentration. The results revealed that this bacterium is capable of producing butanol using all three carbon sources without any treatment. Butanol concentrations of 6. 45، 5. 81، and 4. 64 g/ l were obtained using non-treated starch، treated starch، and glucose as carbon sources، respectively. Discussion and The results suggested the possibility of using non-hydrolyzed starch as carbon source for butanol production. Also it was shown that non-treated starch produces more butanol compared to the treated starch.

In the last decades، increasing petroleum prices، diminishing oil resources، incessant fluctuations in the oil prices and concerns about global shortage of energy resources have boosted research on production and commercialization of biofuels، e. g.، ethanol and butanol، obtained from renewable resources. Besides its application as a fuel، butanol has found numerous industrial applications for the production of plasticizers، lacquers، coatings، detergents، and brake fluids. Biobutanol، together with acetone and ethanol، can be produced in industrial scale by a process called Acetone Butanol Ethanol (ABE) fermentation in anaerobic condition using Clostridium acetobutylicum bacterium. The nature of the carbohydrate and nutrients in the fermentation can affect the ratio of solvents obtained in the ABE fermentation process. In this research، influence of various nutrients and glucose concentrations on the production of butanol by this bacterium was investigated. Results showed that presence of biotin، thiamine، para-amino-benzoic acid، and yeast extract as well as several ions including Mg، Fe، Mn، phosphate، and ammonium acetate in the culture medium is essential for the production of butanol by C. acetobutylicum. Lacks of these compounds in the medium significantly reduced the production of solvents، in spite of the growth of the bacterium. also optimum concentration of glucose was 40g/l for maximum production solvent. In this concentration، maximum solvent concentration was achieved 10. 5 g/l and maximum butanol concentration was achieved 6. 7g/l with yield of 26. 25%.