Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2004
Publication Date: October 21, 2004
Citation: Wilkins, M.R. 2004. Citrus peel ethanol: florida's biofuel for the future. Subtropical Technology Conference Proceedings. 55:40-41.
Ethanol or methyl tertiary butyl ether (MTBE) must be added to gasoline in many areas to increase its oxygen content in compliance with the Clean Air Act. Many states have banned the use of MTBE because it has been found to be a groundwater pollutant. These bans combined with the desire for domestic renewable sources of energy have substantially increased the demand for fuel ethanol from approximately 1 billion gallons per year in 1990 to over 3 billion gallons per year in 2004. Most fuel ethanol in the US is produced from corn in Midwestern states and must be transported by rail, truck or barge to supply markets where corn is not a major crop, such as Florida. Ethanol cannot be transported by pipeline because it absorbs water that may lead to pipeline corrosion, which leads to high transportation costs. Using locally available materials to produce fuel ethanol would allow Florida to replace MTBE with ethanol as an oxygen booster in gasoline and lower transportation costs. One potential feedstock for ethanol production that is abundant in Florida is citrus peel. Approximately 5 million tons of waste citrus peel are annually produced by Florida citrus juice processors. Previous studies on a laboratory scale have enzymatically converted Valencia orange peel to glucose, fructose, galacturonic acid and other sugars. Saccharomyces cerevisiae was then used to ferment six carbon sugars, such as glucose and fructose, into ethanol while Escherichia coil K011 was able to utilize and ferment all sugars and galacturonic acid. This presentation will summarize current efforts to scale up the process for ethanol production from citrus waste.