Ethanol Production Using Continuous Multi-staged Immobilized Microbe Bioreactors: A Laboratory Study
Alternative fuels are important for the United States to reduce their dependence on fossil fuels. Currently, ethanol is the only renewable fuel that is produced in commercial quantity. The demand for ethanol is increasing throughout the world. The production of ethanol is limited by the available feedstocks and processing technology.
Corn is the primary feedstock for ethanol in the United States. It is processed in either the wet milling or dry milling process. Both processes use either the batch or continuous fermentors. Both batch and continuous systems have operational restrictions with maintaining a good growth of yeast and preventing contamination with bacteria.
The use of Immobilized Microbe Bioreactors will provide a continuous system that maintains a growth of yeast and is resistant to bacteria. The Immobilized Microbe Bioreactors are packed with biocarrier which is a solid, porous, inorganic substance that provides a large surface area for attachment of the yeast cells. The yeast colonizes the internal surfaces as well as the external surfaces of the biocarrier. This provides a higher culture density of yeast which is resistant to bacterial contamination.
The feasibility of using the Immobilized Microbe Bioreactor was addressed by laboratory testing. Raw sugar and molasses were used as feedstocks. The Microbubble Generator was tested for the ability to saturate the feed with air to facilitate the growth of yeast. The yield of ethanol was determined by distilling azeotropic ethanol as an overhead product. The data indicated that the Immobilized Microbe Bioreactor could be an improvement to ethanol production systems.
Advisor:Ralph J. Portier; Edward B. Overton; Michael W. Wascom
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Date of Publication:01/18/2008