(145f) A Novel Chemical Pretreatment Method to Accelerate Bioconversion Rate of Renewable Feedstocks

Authors: 
Kang, Y., Georgia Institute of Technology
Realff, M., Georgia Institute of Technology
Bommarius, A. S., Georgia Institute of Technology
Sohn, M. J., Georgia Institute of Technology


Abstract

Lignocellulosic biomass is the most abundant naturally renewable organic resource for biofuels production. Due to its recalcitrance to hydrolysis, pretreatment is a crucial step prior to enzymatic hydrolysis of the feedstock. A variety of pretreatment methods have been intensively studied to achieve optimal yield without imposing significant adverse impact on the environment. Herein, we present a novel and cost-effective chemical pretreatment method using substituted heterocycles in an environmentally friendly way.

Methylimidazole is a precursor to some imidazolium-based ionic liquids. It can be used as a pretreatment agent at mild conditions, i.e. ambient temperature and pressure, for a very short period of time to obtain a substantial increase in the hydrolysis rate throughout the conversion of cellulose substrate. X-ray diffractometry was utilized to study the crystal structure of cellulose and a reduction in crystallinity index was observed, which can be a crucial contributor to the improvement of enzymatic degradation rate. Furthermore, recycling of methylimidazole is possible and we have tested the recyclability by reusing methylimidazole for up to four times without observing marked reduction in the initial 1-hour hydrolysis rate of cellulose. The pretreatment effectiveness of methylimidazole on both original and steam-exploded lignocellulosic biomass has been investigated. Improvement in initial hydrolysis rate was observed for both lignocellulosic substrates.