The role of side-chains of xylan in its biotechnical utilization

Pure xylose has often been used as a model substrate for studying the conversion of pentoses to ethanol and other chemicals. Most of the hemicellulose in hardwoods and agricultural residues is xylan. In this study hemicellulose was separated from birchwood by steaming and water-extraction. The hydrolysis of the hemicellulose fraction was studied using enzymes of Trichoderma reesei and Aspergillus awamori. The acetyl- and 4-0-methylglucuronic side groups of the xylan backbone of birchwood were found to limit the utilization of the raw material in two ways: by affecting the yield in enzymatic hydrolysis and through the inhibitory effect of the released acids