Tuesday, April 20, 2010
LL Conference Facility (Hilton Clearwater Beach)
The production of bio-ethanol has been increased in many countries to use as an alternative fuel. Ethanol stillage is a by-product generated after the distillation of ethanol and its amount can be up to 20 liters for each liter of ethanol produced. Because it contains a high amount of organic matter, its proper treatment is necessary. In this study, it was examined whether ethanol stillage can be used as a medium substitute for the production of bio-butanol. Ethanol stillage contains up to 20 g/L of glycerol, which can be converted to butanol by Clostridium pasteurianum DSM 525. In the presence of up to 9 g/L of lactic acid or 10 g/L of acetic acid, which are the possible inhibitors contained in stillage, C. pasteurianum DSM 525 could produce 6.2~8.7 g/L of butanol from initial concentration of 30 g/L of glycerol without serious inhibition. When the stillage prepared in laboratory or obtained from a distillery was used as a medium, C. pasteurianum DSM 525 produced 6.0~7.2 g/L of butanol from initial concentration of 14.7~21.2 g/L of glycerol. Our results showed that the stillage can provide carbon source, nutrients, and buffering effect for butanol fermentation.