Improvement of biomass properties by pretreatment with ionic liquids for bioconversion process
Leong, Susanna Su Jan
Chang, Matthew Wook
Ching, Chi Bun
Date of Issue2012
School of Chemical and Biomedical Engineering
Cassava pulp residue and rice straw were used as a precursor for pretreatment with ionic liquids to study the effects of pretreatment conditions on product yield and properties. Cassava pulp residue is a potential biomass in the bioconversion process due to it requiring mild pretreatment conditions while providing a high sugar conversion. The maximum sugar conversion and lignin extraction are attained from pretreatment of biomasses with particle size of <38 μm and ionic liquid of 1-Ethyl-3-methylimidazolium acetate at 120 °C for 24 h. The effectiveness of ionic liquid for biomass pretreatment process follows the sequence: 1-Ethyl-3-methylimidazolium acetate > 1-Ethyl-3-methylimidazolium diethyl phosphate > 1,3-Dimethylimidazolium methyl sulfate. The increase of pretreatment temperature from 25 to 120 °C and decrease of biomass particle size renders higher sugar conversion, lignin extraction and lower crystallinity index. However, pretreatment at temperatures higher than 120 °C shows a sharp decline of regenerated biomass yield, sugar conversion and lignin extraction and giving higher crystallinity index at pretreatment temperature of 180 °C.