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

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%.

Cellulase products usage in industry is in demand considerably. This enzyme is used in paper, paint, oil and textile industries. Cellulase can convert cellulose to glucose and then glucose can be converted to ethanol which this process can be replaced with fossil fuels. Cellulose is a polysaccharide that can be renewable and may be in future providing fuel for transportation. Cellulase converts cellulose to soluble sugars. One of the most extensively studied organisms is the soft rot fungus Trichoderma reesei. This fungus produces a complete set of cellulolytic enzymes that are able to cleave β- 1, 4- glycosidic bonds present in cellulose or cellulose derivatives. One of the key enzymes in the multi- enzyme complexes is endoglucanase which is purified from different method. By using the butanol to concentrate this enzyme, we obtained remarkable active enzyme. The amount of cellobiohydrolases are much more than the concentration of endoglucanases (mentioned by several articles) in Trichoderma reesei. In this experiment, we could obtain the concentration of endoglucanases 20% more than cellobiohydrolases.