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Poster Presentation 3-27
Enzymatic Hydrolysis and Simultaneous Saccharification and Fermentation of Wet Oxidized Corn Stover
Enikő Varga1, Helene B. Klinke, Kati Réczey1 and Anne Belinda Thomsen2
1Budapest University of Technology and Economics Department of Agricultural Chemical Technology H-1521 Budapest, St. Gellért tér 4, Hungary
2Risř National Laboratory, Plant Research Department P.O. Box 49., DK-4000 Roskilde, Denmark
Telephone: 36-1-463-3442; Fax: 36-1-463-2598; E-mail: eniko_varga@mkt.bme.hu
Lignocellulosic materials are a potential alternative energy source that can be converted to liquid fuels such as ethanol. The replacement of non-renewable fossil fuels with bioethanol would provide a clean burning fuel that does not add net carbon dioxide to the atmosphere.
Among the available agricultural by-products, corn stover with its yearly 10-million-ton yield is the most abundant, promising raw material for fuel ethanol production in Hungary. Due to the structural features, such as lignin and the highly ordered crystalline structure of cellulose, lignocellulosic biomass is resistant to hydrolysis and only limited and slow conversion occurs without pretreatment. The wet oxidation process, a reaction involving oxygen and water at elevated temperature and pressure, was investigated to enhance the enzymatic digestibility of corn stover. Six different combinations of reaction temperature, time and pH were applied. The best conditions (20 g/L corn stover, 195°C, 15 min, 12 bar O2, 2 g/L Na2CO3) increased the enzymatic conversion of corn stover four times, compared to untreated material. The achieved conversion of cellulose to glucose was about 85% after 24 hours hydrolysis at 50°C using 25 FPU/g DM biomass.
To determine the real efficiency of the pretreatment in the ethanol production, simultaneous saccharification and fermentation (SSF) was performed on alkaline wet oxidized corn stover. Our results showed that the wet oxidation method appears to have the advantage of producing negligible amounts of by-products, like furfural and hydroxymethyl-furfural, because pretreated biomass did not inhibit yeast during the subsequent fermentation stage.
Detailed results of hydrolysis on wet oxidised corn stover, the changes of the lignocellulosic structure and fermentability of pretreated material with baker’s yeast will be presented.
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