Bioethanol is one alternative energy fuel that can be produced from different types of biomass. Second generation bioethanol comes from fermentation of lignocellulosic material and can be seen as a more environmental friendly alternative as e.g. forest residues and agricultural by-products are used. To be able to use lignocellulosic biomass in ethanol production, it has to be subjected to different treatments first. In this study, aspen sawdust was used as lignocellulosic material.