Аннотация:The comparative study of the efficacy of aspen wood biomass pretreatment process followed by enzymatic hydrolysis was performed. Pretreatment includes semi-coarse milling (200-300um particles) followed by prehydrolysis by aqueous solutions of sulfuric and nitric acids, and by organosolve. The influence of acid concentration, temperature, organic phase ratio, and pressure on the efficacy of pretreatment was studied. The increase of organosolve pretreated aspen wood biomass reactionability was 3,5-4 fold to compare to untreated substrate. Nitric acid pretreatment leads to over 5 fold increase of the substrate reactionability.