PRETREATMENT OF LIGNOCELLULOSIC BIOMASS THROUGH REMOVAL OF INHIBITORY COMPOUNDS

摘要

A process for the pretreatment of lignocellulosic biomass is disclosed, which includes the steps of pretreating the lignocellulosic biomass to hydrolyze and solubilize hemicelluloses in the biomass; explosively decomposing the biomass into fibers; and extracting from the resulting solids fraction a liquefied portion of the lignocellulosic biomass before or after explosive decomposition. This removes compounds from the lignocellulosic biomass which are inhibitory to enzymatic cellulose hydrolysis and sugar fermentation to ethanol. For improved economy, the inhibitory compounds are not completely removed. The extraction step is controlled on the basis of the xylose equivalent content in the reaction mixture and the extracting step is discontinued once a xylose equivalent content of 4-8% w/w of xylose in the dry matter of the solids fraction is achieved. This most economically balances the practical need for inhibitory compound removal with the economical need to minimize the costs of the overall ethanol production process.