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Poster Presentation 1-08
Determination of the Microbial Inhibition and Enzymatic Hydrolysis Rates of Carbonic Acid Pretreated Aspen Wood
Damon Yourchisin and G. Peter van Walsum
Department of Environmental Studies, Baylor University PO Box 97266, Waco, TX 76798-7266
Telephone: (254) 710-6552; Fax: (254) 710-2309; E-mail: Gpeter_van_Walsum@Baylor.edu
This study investigated the toxicity to Saccharomyces cerevisiae of hydrolysates produced from carbonic acid pretreatment of aspen wood and the kinetics of enzymatic hydrolysis of solid components produced through this same pretreatment.
Samples produced by the pretreatment of aspen wood with carbonic acid were compared to samples produced using only liquid hot water. Pretreatment temperatures tested ranged from 180oC to 220oC; reaction times were varied between 2.5 and 30.5 minutes; and initial room temperature CO2 pressures ranged from 0 to 800 psig.
Toxicity tests measured the rate of glucose consumption by S. cerevisiae growing in anaerobic batch culture at varying concentrations of hydrolysate. The rate of enzymatic hydrolysis was determined by suspending the pretreated solids in a citrate buffer and measuring sugar production rates at different cellulase loadings in the presence of excess ß-glucosidase. Carbohydrate concentrations were determined via High Performance Anion Exchange (HPAE) chromatography or an enzymatic glucose assay. Toxicity and hydrolysis rate results were compared to the pH and UV-visible absorbance of the hydrolysates and pretreatment reaction severity. Correlations to these variables are discussed.
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