(460a) Defining Enzyme Inhibitors for Cellulose Hydrolysis
AIChE Annual Meeting
2008
2008 Annual Meeting
Sustainable Biorefineries
Biological Conversions and Processes for Renewable Feedstocks
Wednesday, November 19, 2008 - 12:30pm to 12:55pm
Compounds that inhibit the enzymatic hydrolysis of cellulose to fermentable sugars may be present when lignocellulosic materials are pretreated. We have observed the reduction in extent of conversion of pretreated cellulose to fermentable sugars as the solids loading (concentration of solid biomass material) is increased even though the ratio of enzyme to solids material is kept constant. In addition, washing the pretreated cellulosic material results in greater extents of conversion. We have identified various potential inhibitors including ferulic acid and other phenolic compounds which may help to describe this phenomenon. Glucose yield reduction up to 70% for the hydrolysis of wet cake by commercial cellulase and ß-glucosidase in the presence of 0.5% (w/v) ferulic acid were observed in our studies. Comparing enzymes from different microorganism sources, we have also found that some are more resistant to inhibition by ferulic acid than others. This paper describes the chemistry and possible mechanisms for inhibition of industrial cellulase and hemicellulase enzymes by unknown components that are present in lignocellulosic material.