Sunday, April 29, 2007

A new approach to determine cellulose reactivity change with conversion for enzymatic hydrolysis of pretreated corn stover

Bin Yang, Qing Qing, Michael Studer, and Charles Wyman. University of California, Center for Environmental Research and Technology, 1084 Columbia Avenue, Riverside, CA 92507

Corn stover and poplar wood were pretreated by dilute acid, flowthrough with just water, and sodium hydroxide to prepare highly digestible cellulose with significant differences in cellulose history and in removal of hemicellulose, lignin, and other components. Then cellulose reactivity was measured for each substrate versus time and cellulose conversion using a new restart protocol that has been shown to be effective on pure cellulose, and the results were compared with those for uninterrupted hydrolysis of the same materials. Bovine serum albumin (BSA) was also applied to these substrates prior to adding enzymes to substantially reduce non-productive cellulase adsorption on lignin. Loss of cellulose over time was measured through application of standard analytical procedures and determine the initial hydrolysis rate versus conversion and time. Finally, cellulose reactivity was evaluated for comparison of restart to uninterrupted hydrolysis data to better understand whether this technique alters substrate features or enzyme action.