Tuesday, April 30, 2013
Exhibit Hall
Xylan in biomass is often highly acetylated. During low-severity dilute acid hydrolysis, the depolymerization of xylan to xylose involves two reactions: 1) hydrolysis of xylosidic bonds, and 2) hydrolysis of ester bonds between xylose subunits and acetyl groups. Approximately 40% of the xylose units in native corn stover are linked to acetyl groups, suggesting 40% of the xylose monomer units formed in acid hydrolysis require both reactions to take place. However, many previous kinetic studies on acid hydrolysis of xylan only modeled the depolymerization of unsubstituted xylan, with no acetyl side chains, ignoring the impact of the 2nd reaction described above. In addition, our previous studies on low-severity dilute acid pretreatment of deacetylated corn stover suggests that this previously overlooked reaction could be the rate limiting step to the formation of monomeric xylose in dilute acid pretreatment. Therefore in this study, we used both acetylated and non-acetylated xylan model compounds, extracted by DMSO from native corn stover, to study the kinetics of xylan hydrolysis in dilute acid pretreatments. A kinetics model incorporating acetyl group hydrolysis has been developed and will be compared using experimental data.