ИСТИНА

Many types of biomass, such as wood, agricultural waste, grassy crops and solid rural waste are considered as a stock suitable to produce ethanol. Woody biomass is mainly composed of lignocellulosic material, which is constituted of cellulose (40–50%), hemicellulose (20–40%), and lignin (20–30%). It displays rather high resistance to enzymatic hydrolysis. Semi-bleached sulfate hardwood and craftwood pulp are semi-finished products of the pulp-and-paper industry. They does not require any additional pretreatment to perform effective enzymatic conversion into monosaccharides [1]. Major enzymes involved in lignocellulose conversion to fermentable sugars are cellobiohidrolases (CBH), endoglucanases (EG), b-glucosidases (bG), polysaccharidemonooxygenases (PMO), and endo-xylanases (eXyl) . The cooperative action of these enzymes leads to efficient C6/C5 sugars production from biomass [2]. The effectiveness of semi-bleached sulfate hardwood pulp hydrolysis by enzyme preparations with predominant content of CBH (#1), CBH/EG (#2), CBH/EG/eXyl (#3), and CBH/eXyl (#4) was studied. The highest initial rate of substrate solubilization and monosacchride formation, with the conversion up to 95% was observed for enzyme preparation #4 for 100-300 g/L of initial substrate concentrations. The efficiency of pulp conversion to simple sugars was even higher in case of preparation #4 dopped with bG and PMO – the rate of glucose formation, as well as substrate viscosity reduction and solubilization were the highest. 1. Novozhilov E., Sinelnikov I., Rozhkova A., Zorov I., Sinitsyn A. Biocatalytic Conversion of Kraft Pulp Using Cellulase Complex Penicillium verruculosum. Kataliz v promyshlennosti. 2015;15(5):78-83. (In Russ.) (doi 10.18412/1816-0387-2015-5-78-83). 2. Contreras, F.; Pramanik, S.; M. Rozhkova, A.; N. Zorov, I.; Korotkova, O.; P. Sinitsyn, A.; Schwaneberg, U.; D. Davari, M. Engineering Robust Cellulases for Tailored Lignocellulosic Degradation Cocktails. Int.J.Mol.Sci. 2020, 21, 1589 (doi 10.3390/ijms21051589).