ИСТИНА

Processing of the Russian cellulose-containing raw materials Ivan Zorov, Dmitry Osipov, Margarita Semenova, Arkady Sinitsyn Chemistry Department, MV Lomonosov Moscow State University, Moscow, Russia, 119991 Federal Research Centre «Fundamentals of Biotechnolgy» Russian Academy of Sciences, Moscow, Russia, 119071 e-mail: inzorov@mail.ru One of the biggest world's forest resources (around 20%) are concentrated in Russia. According to this indicator, the Russia is in second place after Brazil. The presence of rich natural wood reserves attracts investment in the industry, stimulates production growth and export development. In percentage terms, the processing of wood at the sawmill yields about 60% of raw materials. The remaining 40% is waste, they contain 14% - slab, 12% - sawdust, 9% - cuts and small things, the rest is bark or end cuts. The optimal solution to the problem of using sawmill waste is the development of joint technologies with energy companies that are interested in the supply of fuel products. Processing of cellulose-containing raw materials (CCRM) should be divided into three successive stages: pretreatment of CCRM by physical and chemical methods; enzymatic hydrolysis of pretreated CCRM using complex of enzymes to simple sugars - hexose (C6) and pentose (C5); microbiological conversion of sugars into products of microbiological synthesis (bioethanol etc.). Pretreatment of CCRM is extremely important for the success of further stages. It allows you to partially amorphize strong crystalline structures of cellulose, which provides better access for enzymes to polysaccharides of the plant cell wall (cellulose, hemicellulose, pectin, etc.). For wood and bagasse, 4 different pretreatments were optimized: dilute sulfuric acid (0.5-0.7%, 120-130°C, 15-25 min), dilute nitric acid (1.35-1.5%, 175-180°C, 15-40 min), diluted alkali solution (1-2%, 170-180 °C, 50-60 min) and white liquor (160-170 °C, 15-30 min). Also, the enzymatic hydrolysis was optimized using cellulase preparations obtained on the basis of the dried cultural fluids of the fungus Penicillium verruculosum. It is shown that the best pretreatment option for wood is white liquor (NaOH/Na2S) for 15 minutes at 170 °C, and for bagasse a dilute solution of alkali. These types of pretreatments provide yields of up to 60 and 80 g/L of glucose, respectively.