Date of Award

12-2011

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Advisor

G. Peter van Walsum

Second Committee Member

Adriaan R.P. van Heiningen

Third Committee Member

Raymond C. Fort

Abstract

As the energy demand for transportation grows and fossil fuel resources, which are now the major source for transportation fuels, are diminishing; biomass-originated fuels are gaining more attention. Generally there are three stages in making cellulosic bioethanol: pretreatment, enzymatic hydrolysis and fermentation. The aim of this research is to characterize and identify inhibitors of enzymatic cellulose hydrolysis acting under different combinations of feedstock and pretreatment processes. In order to achieve this aim, we need to develop a rapid and effective method for measuring glucose which is released through the enzymatic hydrolysis step. Pretreatment of biomass was done using a Dionex Accelerated Solvent Extractor. The Yellow Spring Instrument (YSI) glucose analyzer was assessed for its suitability, and then used as a tool for rapid glucose measurement of the enzymatic hydrolysis system. The data from enzymatic hydrolysis of Avicel in the presence of six different pine flour hydrolysates showed that both initial rate of glucose production and the final glucose concentration achieved for each reaction were higher in the hydrolysate pretreated at higher pH conditions. The six pretreatment conditions tested included dilute acid, liquid hot water, phosphate buffer, aqueous ammonia, magnesium hydroxide and calcium hydroxide. Studying the concentration of the thirty seven different analytes suggest that some of them had inhibitory effects on the enzyme. Most of these compounds are aromatics with three or more groups on the ring which is a similar shape of glucose, so it is likely that they are inhibiting the cellulase competitively.

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