| Abstract [eng] |
Worldwide fossil fuel resources are running out. Energy consumption is an essential part of modern human life. Bioethanol is a perfect alternative to petrol produced from oil. Furthermore, it is widely used in alcoholic drinks, chemical, and pharmaceutical industry. Bioethanol is produced by yeast in a process called alcoholic fermentation. During this anaerobic reaction a sugar molecule is transformed into ethanol and carbon dioxide. The most commonly used microorganism for this process is yeast Saccharomyces cerevisae. Recently, research is being performed in search of cheaper, more applicable raw materials and optimization of reaction conditions in order to make bioethanol production as efficient as possible. It is important to make bioethanol production economical and repeatable. This way its price could compete with and reduce production of oil-derived fuel. In this thesis 4 different carbon sources, mono- and disaccharides, were used in order to find out which is the best for bioethanol production. Two types of wheat “Famulis” and “Etana” were investigated. After choosing the most suitable type of wheat, a search of an enzyme was performed. Glucoamylase and cellulase were analyzed. In this research it was determined that the most suitable sugar for bioethanol production is monosaccharide glucose. Fermentation in 5 L fed-batch bioreactor “EDF-5.4” was performed using glucose. This investigation showed how speed of bioethanol production is dependent on glucose concentration in medium. In the current research it was shown that bioethanol could be produced from various monosaccharides and disaccharides and the most suitable is glucose. The amount of bioethanol produced from wheat could be increased by employing appropriate enzymes and its concentrations. According to the results gathered using fed-batch bioreactor, optimal glucose concentration interval which induced the highest relative speed of bioethanol production was determined. |
