Tuesday, April 30, 2013
Exhibit Hall
Furfural, as one of the key chemicals from projected lignocellulosic biorefineries, is currently mass-produced from the pentose-based hemicellulose fraction (20-30% xylan) of lignocellulosic biomass, such as sugarcane bagasse and corncobs. However, the cellulose-rich solid fraction (30-50% glucan), a key substrate for other products, is mostly under-utilized as boiler fuel. In our study, we converted the C5 hemicellulose sugars (xylan) of Miscanthus and sugarcane bagasse into furfural at 170°C-200°C for 10 min under acid conditions (1% H2SO4), followed by solubilization of the glucan-rich fraction using switchable butadiene sulfone at 70°C for 24 h for potential processing to value-added products. This solvent has the ability to “switch” in equilibrium from solvent to 1,3-butadiene and sulfur dioxide, forming sulfurous acid in the presence of water. The solvent-acid dual attack to the remaining solids after furfural production allows for acid hydrolysis of any remaining C5 sugars and the partial solubilization of lignin by butadiene sulfone. The yield of furfural from Miscanthus was up to 57% of the original xylan content with some unwanted degradation of cellulose into levulinic acid, hydroxymethylfurfural and formic acid. Following a water wash, switchable butadiene sulfone solubilized 30% of the solids. The liquids were separated via vacuum filtration to isolate the exposed glucan for downstream enzymatic hydrolysis and fermentation. The utilization of both cellulose and hemicellulose to produce value-added products will contribute to a sustainable approach for bioenergy production.