| The principal objective of this study was to demonstrate the technical feasibility of fermentation inhibition removal from acid hydrolyzates of lignocellulosic materials and recovery of the by-products of acid hydrolysis as chemicals of value.; The acid hydrolyzates of mixed hardwoods were produced from the continuous flow demonstration unit (CFDU) at the University of California Forest Products Laboratory. Two separate liquid product streams were the prehydrolyzate (S1H) and the second stage hydrolyzate (S2H). Candida utilis NRRL Y-900 and Saccharomyces cerevisiae NRRL 2034 were used to monitor the fermentability of these two product streams, respectively.; Two pretreatment methods were investigated in detail: flashing and solvent extraction. For the S1H, flashing was adequate to enable cell production with Candida utilis. The S2H rehired solvent extraction to ensure ethanolic fermentation at high concentrations of glucose (12% or higher). A solvent was selected for the extraction process and process flow designs were proposed to recycle the solvent and isolate commercial by-products, including furfural, methanol, acetic acid and, potentially, formic acid, levulinic acid and 5-hydroxymethylfurfural. |
