ИСТИНА

Modern world faces a number of key challenges, among all, there has to be a transition from the society based on fossil resources to a more sustainable one with a growing contribution of renewables for energy and materials. Enzyme technology will be used for the conversion of agricultural and forestry stocks into a wide variety of fine and bulk chemicals, bioplastics, biofuels, pharmaceuticals etc. At present, the use of renewable feedstock, such as agricultural byproducts are gaining importance as starting material for future biotech products. Agricultural and forestry materials, including (ligno)cellulose or starch are first converted into sugars, which are subsequently transformed into a wide range of products, including ethanol, via fermentation. The strategy of achieving the results comprise the regional competitive biomass feedstock, rational pretreatment process (physical, chemical or combination of them), as well as strain development and fermentation conditions optimization. Pretreatment step should efficiently increase the reactionability of biomass selected while creating the minimal amount of toxic impurities for the further process steps as well as for the environment. Fine milling, organosolve, alkaline treatment, and ionic liquids (IL) seems to be prospective in terms of efficiency, relatively low cost, and low environmental footprint. Those pretreatment methods reduces the lignin content while drastically improve cellulose reactionability during enzymatic step. The mycelial fungus Penicillium verruculosum produces a complex of highly active enzymes for the degradation of pretreated lignocellulose feedstock like woody byproducts, straws, bagasse, and other. The enzyme complex secreted by the fungus above contains exo- and endo-cellulases (CBHs and EGs) and beta-glucosidase (BG), xylanases (XYN) as well as lytic polysaccharide mono-oxygenases (LPMOs). To fit the substrate composition used the enzymes properties and their ratio in the preparation can be altered by protein and genetic engineering as well as in fermentation optimization process. The basal enzyme complex produced by P. verruculosum consists of 55-65% of CBHs, 20-22% of EGs, 2-3% of BG, and 12-15% of XYNs. The significant (up to 25-30% of simple sugar release) boosting during hydrolysis of aspen wood, bagasse, and high kappa pulp pretreated with organosolve and alkaline solution was detected at the presence of 8-10% of BG and 2-3% of LPMO in the enzyme complex. Microbial synthesis step of valuable building blocks from sugar hydrolysates could be sensitive to the impurities formed at pretreatment process. Ethanol fermentation is much more tolerant to residual chemicals (acetate, ILs) in hydrolysates to compare to oxycarboxylic or dicarboxylic acids production. Special plastics production based on microbial fumaric acid requires careful pretreatment and additional purification of steps after enzymatic hydrolysis and fermentation.