The improvement of enzymatic hydrolysis efficiency of rape straw and Miscanthus giganteus polysaccharides

•Polysaccharides of rape straw and miscanthus were hydrolyzed with hydrolytic enzymes.•Experiments were conducted with native and alkaline pretreated substrates.•The study demonstrates a significant impact of xylanases on the hydrolysis yield. The research was carried out with the aim to determine the impact of various combinations of cellulase and hemicellulase preparations on the effectiveness of enzymatic hydrolysis of polysaccharides of rape straw and Miscanthus giganteus after alkaline pretreatment. Their effectiveness was evaluated based on the quantity of saccharides released during enzymatic reaction and yield calculated in respect of the sum of polysaccharides present in native substrates. The complex of preparations produced from Trichoderma longibrachiatum fungi turned out to be the most effective. The study demonstrated a significant effect of xylanases from T. longibrachiatum, the presence of which evoked a 27–45% increase in the effectiveness of polysaccharides hydrolysis compared to the enzymatic complexes without their addition. In addition, results achieved in this study confirmed the necessity of applying the pretreatment in lignocellulose substrates conversion into bioethanol.