(787g) Crystallinity – A Rate-Determining Parameter for Pretreated Lignocellulosic Biomass

Yuzhi Kang, Prabuddha Bansal, Bryan Vowell, Matthew Realff, Jay Lee, Andreas Bommarius

Abstract

Steam explosion is one of the most effective pretreatment methods in disrupting lignocellulosics structure and enhancing its accessibility. The effects of steam explosion on woody biomass and agricultural residues (i.e. bagasse, wheat straw and loblolly pine) are evaluated. The key operational parameters including temperature, residence time and acid concentration have pronounced effects on crystallinity index (CrI) of the feedstock. The CrI of steam-pretreated lignocellulosic biomass was calculated from X-ray diffractometry with the method of Least-squares and was found to decrease as pretreatment severity increases. A series of steam-exploded lignocellulosic samples with varying CrI was generated and the significance of CrI is confirmed by a linear relationship between initial hydrolysis rates and CrI. The present study provides evidence that the CrI is one of key parameters determining the enzymatic hydrolysis rate of pretreated lignocellulosic biomass.

To more fully explore the connection between accessibility, hydrolyzability and reactivity, we have undertaken experiments with phosphoric acid swollen Avicel^® at different levels of conversion. We will present the quantitative trends between the rate of conversion and these underlying substrate properties.