| Abstract: | Acid and alkali pretreatments were studied to identify those factors which are critical in determining the susceptibility of a lignocellulosic substrate (bagasse) to enzymic hydrolysis. The different effects of each treatment on the structure of the bagasse affected the subsequent susceptibility to enzymic attack in different ways. The acid treatments appeared to act by disrupting the lignin structure, probably by hydrolysing the carbohydrate chains attached to the lignin, as well as the lignin itself. The attack on the carbohydrate content removed outlying material in the cell wall (i.e. hemicellulose and amorphous cellulose) to expose a ‘core’ of more resistant regions. The alkali treatments appeared to produce a more open structure by penetrating the inner layers and selectively removing hemicellulose molecules as well as breaking some lignin—carbohydrate bonds. The different treatments resulted in structural changes which were found to affect the hydrolysis mechanism. |
