Volodko O. Development of Technological Bases for Bioethanol Obtaining from Sweet Sorghum

The dissertation is devoted to the study of the peculiarities of preparation and alcoholic fermentation of sugars of sweet sorghum juice and syrup by yeast Saccharomyces cerevisiae, analysis of mature culture liquid, bard and bagasse of sweet sorghum. Technological solutions for obtaining, purifying juice, preparation of fermentation wort are scientifically substantiated, conditions of alcohol fermentation of sugar-containing juice and sweet sorghum syrup are optimized. The technological scheme of bioethanol production from sweet sorghum is developed taking into account modern technical and economic requirements. The biotechnology of fermentation of sugar-containing sweet sorghum juice has been adapted to the already existing bioethanol productions on the territory of Ukraine which are working on sugar beet molasses. It was recommended to use two-stream fermentation with feeding the medium with a thicker wort for the increasing the efficiency and productivity of sorghum sugar fermentation. It was shown that the use of vacuum increases the intensity of fermentation, but also has significant requirements for fermentation equipment and process control. The calculation of the sweet sorghum cluster of material flows and energy needs to obtain initial data in the design of the plant was performed, the possible production cost of bioethanol from sweet sorghum was calculated ($ 0.3/l). The possibility of full self-sufficiency of the plant with thermal energy due to the burning of sorghum stalks was established. The chemical composition and methods of processing by-products of sweet sorghum stalks into bioethanol have been studied. The fodder value of sorghum bagasse was established.