Sunday, May 4, 2008
3-37
Dilute acid hydrolysis of wheat straw oligosaccharides
L. C. Duarte, T. Silva-Fernandes, F. Carvalheiro, and F.M. Gírio. Departamento de Biotecnologia, INETI, Estrada do Paço do Lumiar, 22, Lisboa, 1649-038, Portugal
Among the promising biomass pre-treatment options available (e.g. autohydrolysis, steam explosion, alkaline and organosolv treatments), many produce a sugar rich liquid stream derived from selective hemicellulose solubilization. Unfortunately, the sugars present are typically in oligomeric form. The hydrolysis of these hemicellulosic oligosaccharides, is a compulsory requirement for direct fermentation to ethanol, as there are not yet any effective microbial catalyst that can directly metabolize them. The posthydrolysis options can be reduced to acid or enzymatic catalyzed hydrolysis, with acid hydrolysis typically presenting both higher yield and productivity.
In this work the dilute acid posthydrolysis of wheat straw hemicellulosic oligosaccharides obtained by autohydrolysis was evaluated. We have used a Doehlert experimental design to study the effect of catalyst concentration (sulfuric acid, 0.1-4% w/w) and reaction time (0-60 min) in order to maximize monosaccharide recovery and minimize byproduct formation. Both the main effects are statistical significant for sugar recovery and interaction effects also play a significant role. Conversely byproducts concentration is mainly affected by acid concentration.
Under the optimized conditions it was possible to obtain a significant increase in monosaccharides content (above 15%) together with a slight decrease in inhibitors content compared to the standard acid hydrolysis treatment. Furthermore this is achieved with a close to 60% less acid spending.
This work has been funded by CEBio (AdI) and BIOREFINO (FCT) projects.
In this work the dilute acid posthydrolysis of wheat straw hemicellulosic oligosaccharides obtained by autohydrolysis was evaluated. We have used a Doehlert experimental design to study the effect of catalyst concentration (sulfuric acid, 0.1-4% w/w) and reaction time (0-60 min) in order to maximize monosaccharide recovery and minimize byproduct formation. Both the main effects are statistical significant for sugar recovery and interaction effects also play a significant role. Conversely byproducts concentration is mainly affected by acid concentration.
Under the optimized conditions it was possible to obtain a significant increase in monosaccharides content (above 15%) together with a slight decrease in inhibitors content compared to the standard acid hydrolysis treatment. Furthermore this is achieved with a close to 60% less acid spending.
This work has been funded by CEBio (AdI) and BIOREFINO (FCT) projects.
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)