INTRODUCTIONCurrently, the task of finding alternative energysources that are environmentally safe and economicallyaffordable is very urgent. Of particular interest arespecies of herbaceous plants with a high growth rate,characterised by high values of the above-groundvegetative mass growth and having practical applicationas an energy source [1].An example is the genus Miscanthus plants, apractically inexhaustible source of renewable rawmaterials in the field of alternative energy. This is duenot only to the chemical properties of their biomass,but also to high growth rates and enormous biologicalproductivity, among other things in a temperate climate,which together make their use in Russia promising [2].The main advantages of miscanthus biomass incomparison with other types of perennial grasses areassociated with its higher productivity, resistance toadverse environmental conditions, increased lignincontent and, consequently, increased calorific capacity.In addition, the genus Miscanthus plants canbe used to produce biologically active substances.Miscanthus extracts include fatty acids, sterols andother aromatic compounds. The main structuresof phenolic compounds and sterols of the bark andcore of Miscanthus × giganteus include vanilla acid,para-coumaric acid, vanillin, para-hydroxybenzaldehyde,syringaldehyde, campesterol, stigmasterol,β - sitosterol, stigmast-3,5-diene-7-one, stigmast-4-ene-3-one, stigmast-6-ene-3,5-diol, 7-hydroxy-β-sitosterol and7-oxo-β-citerol [3].Currently in the world there is an increase incultivation of Miscanthus driven by the characteristicCopyright © 2019, Babich et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 InternationalLicense (http://creativecommons.org/licenses/by/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix,transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license.Foods and Raw Materials, 2019, vol. 7, no. 2E-ISSN 2310-9599ISSN 2308-4057Research Article DOI: http://doi.org/10.21603/2308-4057-2019-2-403-411Open Access Available online at http:jfrm.ruMiscanthus plants processing in fuel, energy,chemical and microbiological industriesOlga O. Babich1 , Olga V. Krieger1,* , Evgeny G. Chupakhin1 , Oksana V. Kozlova21 Immanuel Kant Baltic Federal University, Kaliningrad, Russia2 Kemerovo State University, Kemerovo, Russia* e-mail: olgakriger58@mail.ruReceived August 26, 2019; Accepted in revised form September 10, 2019; Published October 21, 2019Abstract: The increasing shortage of fossil hydrocarbon fuel dictates the need to search for and develop alternative energy sources,including plant biomass. This paper is devoted to the study of the Miscanthus plants biomass potential and the analysis of technologiesof its processing into products targeted at bioenergy, chemistry, and microbiology. Miscanthus is a promising renewable raw materialto replace wood raw materials for the production of chemical, fuel, energy, and microbiological industries. Miscanthus is characterisedby highly productive (up to 40 tons per one hectare of dry matter) C4-photosynthesis. Dry Miscanthus contains 47.1–49.7% carbon,5.38–5.92% hydrogen, and 41.4–44.6% oxygen. The mineral composition includes K, Cl, N and S, which influence the processesoccurring during biomass combustion. The total amount of extractives per dry substance lies in the range of 0.3–2.2 % for differentextraction reagents. Miscanthus has optimal properties as an energy source. Miscanthus × giganteus pellets showed the energyvalue of about 29 kJ/g. For the bioconversion of plants into bioethanol, it is advisable to carry out simultaneous saccharification andfermentation, thus reducing the duration of process steps and energy costs. Miscanthus cellulose is of high quality and can be used forthe synthesis of new products. Further research will focus on the selection of rational parameters for processing miscanthus biomassinto products with improved physical and chemical characteristics: bioethanol, pellets, industrial cellulose, bacterial cellulose,carbohydrate substrate.Keywords: Miscanthus, bioethanol, cellulose, raw materials, processingPlease cite this article in press as: Babich OO, Krieger OV, Chupakhin EG, Kozlova OV. Miscanthus plants processing in fuel,energy, chemical, and microbiological industries. Foods and Raw Materials. 2019;7(2):403–411. DOI: http://doi.org/10.21603/2308-4057-2019-2-403-411.404Babich O.O. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 403–411high growth rates and a high degree of its biologicalneeds compliance with agro-climatic conditions.The purpose of this review was to analyse themodern methods of processing Miscanthus plantsfor bio-ethanol production, technical and bacterialcellulose, as well as products for microbiological andbiotechnological industry.STUDY OBJECTS AND METHODSThe representatives of the genus Miscanthus(Miscanthus Anderss L.) graminoid family (Poaceae)were the materials of this research. We analysedbotanical characteristics and geographical distributionof various studied plants, made chemical compositionanalysis, and summarised the main processing methodsaccording to the sources of scientific literature. Theseresulted in the analysis of modern methods of obtainingproducts for fuel, energy, chemical and microbiologicalindustries.RESULTS AND DISCUSSIONThe botanical characteristics and distributionof the genus Miscanthus plants. The Miscanthusfamily includes about 40 species of monocotyledonousherbaceous perennial, sustainable plants with longcurved linear leaves and small buds that bloom in latesummer or early autumn, and about 20 species ofmiscanthus proper (Fig. 1).In the Russian Far East (Primorsky Krai, Sakhalinand the Southern Kuril Islands), there are three speciesof miscanthus: Miscanthus sinensis, Miscanthussacchariflorus and Miscanthus purpurascens. It cangrow in the climatic conditions of Central and EasternEurope [4]. In the late 20th century there appeared newmiscanthus genotypes adapted to growth in the Northernregions, including Russian territories.For the countries of the European Union (EU) it isrecommended to grow miscanthus in the continentalclimate zone and the North Mediterranean, where soiland climatic resources correspond to the requirements ofthe plants [5, 6].In Europe the plants reach a height of 3–4 m, andthe representatives of tropical and subtropical speciesmay reach 5 m or more in warm and humid climaticconditions. In the Central part of Russia, according toresearch of scientists of the Russian Timiryazev StateAgrarian University, miscanthus giant reaches the heightof 2 m, in Western Siberia – 2.5 m, and 3.9 m in themiddle Volga region. The stems are upright and resistantto lodging because of their considerable thickness. Itreaches 6 cm in homeland regions (China, Japan, RussianFar East, USA East coast); in the Middle Volga regionsplants of 1–4 years of life are 0.8–1.5 cm thick [7, 8].Miscanthus does not impose high requirements to soiland can grow well on marginal and low density soils whosegranulometric composition is dominated by sand fractions.In Ukraine it is cultivated on sod-podzolic type of soils; inthe forest-steppe of Novosibirsk Priobye, Middle Volga andMoscow region – on gray forest soils [9, 10].For optimal growth and development plants requirecertain thermal and water regimes. Miscanthus seedgermination requires ≥ 20°C soil heating with soilmoisture of 60–80% of full field moisture capacity. Toresume the shoots and the active growing season oncrops of previous years, the temperature of the air mustbe in the range of 20–25°C. As shown in the literature,physiological activity of the studied representatives ofthe genus is sharply reduced at temperatures below 6°С.Optimal temperature for adequate photosynthesisis considered to be 28–32°С. In Eastern Europe this isenough to produce sufficiently high yields of biomass [11].It is known that miscanthus belongs to the C4plants, characterised by: optimum temperature forphotosynthesis of 30–45°C, 40–80 mg/dm2h CO2assimilation in full sunlight, more economical waterconsumption as compared to C3 plants (twice and more),high drought and heat resistance, salt tolerance. Theselead to better assimilation activity and, consequently,biological productivity.The vast majority of well-known scientificstudies are devoted to the three species of the genusmiscanthus: Miscanthus giganteus, Miscanthus sinensisand Miscanthus sacchariflorus, which are the mostwidespread in Russia and abroad [12].Chinese miscanthus (M. sinensis) is one of the mostcommon types of ornamental grasses, named differentlyin different countries. For example, ‘Chinese silvergrass’ or ‘magic grass’, sometimes ‘Chinese reeds’. Innature it is widespread in the Russian Far East up to thetaiga zone, also in China, Korea, Japan. As an adventivespecies it occurs in many countries, e.g. USA, Brazil andAfrican States (Fig. 2) [13].M. sacchariflorus is a species growing on wetmeadows, forest clearings a Figure 1 Chinese Miscanthus ‘Gracillimus’ nd stony slopes in the405Babich O.O. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 403–411Primorsky Krai, China, Korea, Japan, and also in theabove-mentioned areas [14].This also is a perennial long-stem herb up to 2 min height. Stems are erect, thick and numerous. Leavesare rather rigid, linear, flat, long-acuminate, 7–18 mmwide, up to 60 cm long. Flowers are small, in spikeletswith long, white, silky hairs. Inflorescence is 15–25 cmlong, pinkish-silvery, white, fan-shaped, consisting of8–20 spiciform branchlets with fruits. It blooms in lateAugust–September. Flowering often occurs in July [15].Not demanding to soil fertility.Giant miscanthus (Miscanthus × giganteus), asdescribed above, has a C4 photosynthetic path andprovides high productivity of plant biomass. The genomeof this species includes a triple set of chromosomesthat do not divide during meiosis because gametes arenot viable. As a rule, seeds are formed sterile, whichsignificantly limit reproduction of the species, this is abarrier to the establishment of new fields.The rhizome structure of giant miscanthus growsvery slowly and decreases proliferation [16, 17].Therefore, planting material is produced by cultivationof mother plantations (Queen cells), pre-multiplyingit in vitro, or by rhizomes by targeted separation fromplants of the previous planting year. This technologyis limited by insufficient amount of seedling materialand the lack of landing equipment [18, 19]. In thisregard, high-quality uniform planting material canbe grown in special nurseries with the use of modernbiotechnologies.Chemical composition and properties of genusMiscanthus plants. Analysis of miscanthus chemicalcomposition biomass allows planning proper use ofspecies. The three main components of lignocellulosicmaterials are: cellulose, hemicellulose and lignin. Theircontent in each organ is not equivalent and depends onthe plant’s functional and physiological properties. Theamount of cellulose in the stem, as a rule, is higher thanthat in the leaves. Lignin contains three-dimensionalphenylpropyl-based polymer that provides structuralrigidity and integrity, as well as prevents lingocelluloseswelling [20–22].Table 1 shows the differences in concentration ofthese substances in the cell wall in the three speciesgrowing on the territory of European countries, after3–5 years of cultivation [14].According to the data presented in the table, thetypes of miscanthus giganteus and sacchariflorusdiffer insignificantly in pulp content and hemicellulose/lignin ratio.Table 2 shows the averages of biochemicalcomposition of leaves, stems and a whole 4-year-oldplant of Miscanthus varieties [4].Data analysis indicates that the stem of miscanthusis the most suitable raw material for obtaining a largeamount of high quality cellulose, as it has lower contentof ash and lignin and a higher yield of the target product.In the process of turning cellulose into ethanolsuch indicators as degree of polymerisation (n) andits crystallinity are of supreme value. The number ofglucose units that make up one polymer molecule iscalled the degree of polymerisation.X-ray diffraction and solid state 13 CP/MASNMR spectroscopy are the two most commonly usedmethods of cellulose crystallinity determination. Thecrystallinity of cellulose for the species Miscanthussinensis was measured by X-ray diffraction. Subject tothe dimensions of the particles, differences in the indexof cellulose crystallinity were revealed (Table 3) [23].Figure 2 Distribution of Chinese Miscanthus (M. sinensis)Figure 3 Distribution of M. sacchariflorusTable 1 Composition of miscanthus species cell wallsSpecies Cellulose, % Hemicellulose, % Lignin, % H:L ratioM. × giganteus 50.34–52.13 24.83–25.76 12.02–12.58 2.06–2.05M. sacchariflorus 49.06–50.18 27.41–28.11 12.10–12.13 2.26–2.30M. sinensis 43.18–45.52 33.83–33.98 9.69–10.32 3.49–3.29406Babich O.O. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 403–411It is generally believed that cellulose crystallineregions are harder to decompose than amorphousdomains, due to the strong intermolecular hydrogenbonds. For the studied species, the researchers foundthat the initial rate of cellulose hydrolysis increased withdecreasing crystallinity [24, 25].Unlike cellulose, hemicelluloses have lower degreeof polymerisation, typically 50–300; they also have abranched structure and are amorphous. The predominanthemicellulose polymer for the miscanthus is thearabinoxylane, which contains a chain of 1.4-linkedxylonic links. Sugar components in hemicellulose canparticipate in the formation of lignin-carbohydratecomplexes (LCC) by covalent linkages between ligninand carbohydrates.Despite considerable analytical studies aimedat the characterisation of the LCC, they still remainpoorly defined, and their biosynthesis pathways requirefurther study [26]. Distribution, structure and content oflignin is considered to be one of the important factorsresponsible for the recovery of lignocellulosic enzymaticdegradation.Considering miscanthus as fuel, the values ofspecific heat of combustion, mineral composition, ashcontent and content of volatile substances were analysed.The specific heat of combustion parameter is closelylinked to the elemental composition and ash content. ForMiscanthus × giganteus it ranges from 17 to 20 MJ/kg.Dry raw material contains on average 47.1–49.7%carbon, 5.38–5.92% hydrogen, and 41.4–44.6% oxygen.Mineral composition includes the following elements:K, Cl, N and S, which have an impact on the processesoccurring during biomass combustion [27].Increased content of K and Cl can reduce the meltingpoint of ash and cause corrosion. High concentrations ofN and S can lead to increased NOx and SO2 formationduring combustion. Miscanthus mineral concentrationvaries depending on the type of plant, place of growth,time of harvest and even the type of fertilisation. Lateharvest is the preferred fuel due to the lower contentof K, Cl and N. Some studies provide the trace elementcomposition of the miscanthus: S – 0.7–1.9 g/kg, Ca – 0.5–1.4 g/kg, Mg – 0.2–0.6 g/kg, P – 0.4–1.1 g/kg [28].Ash content is an important parameter for fuel.The indicator represents the mass fraction of noncombustibleresidue (calculated as anhydrous weight)percentage, which results from mineral impurities ofthe fuel during its complete combustion. According togeneralised data, miscanthus ash consists of 20–40%SiO2, 20–25% K2O, 5% P2O5, 5% CaO and 5% MgO.Its composition depends on the content of silt and clayin the soil. High ash content leads to the formation ofslag and causes thermal process agglomeration, therebylowering combustion efficiency of biomass plant [29].Biomass high moisture content impedes itscombustion, causing a problem of transportation.Moreover, in the process of wet fuel combustion, alarge number of volatile side-products are released.Table 4 shows composition of volatile products, ashcontent, and molar internal energy (Ea) of miscanthus.The parameters presented are influenced by the harvestperiod, plant species, and climate [30].In addition to biofuels production, the Miscanthusplants can be used for obtaining biologically activesubstances. The total amount of extractives based on thedry substance is redistributed in the range of from 0.3to 2.2% with different extraction reagents. Also morethan 20 hydroxycinnamic acids and their derivativeswere discovered and described. The interest in thesecompounds is justified by the potential of plant phenolsTable 3 Miscanthus cellulose crystallinity according to thediffraction of X-raysParticle size, μm Cellulose crystallinity, %250–355 54.2150–250 50.763–150 41.9< 63 24.8Table 2 Chemical composition of the Soranovski plant varietyThe organs of the plant Performance (in terms of dry substance, %)WGF* ash content lignin pentosan cellulose by KürschnerWhole plant 4.98 ± 0.05 5.87 ± 0.05 22.0 ± 0.5 21.0 ± 0.5 53.1 ± 0.5Leaf 6.32 ± 0.05 9.23 ± 0.05 23.6 ± 0.5 20.3 ± 0.5 43.3 ± 0.5Stem 2.68 ± 0.05 2.13 ± 0.05 15.0 ± 0.5 23.0 ± 0.5 55.7 ± 0.5*WGF – wax glaze fractionTable 4 Energy characteristic of the genus Miscanthus plantsSpecies Ash, %* Moisture, % Volatile matter, %* Coke residue, %** Ea, kJ/molM. × giganteus 2.7 4.2–4.9 73.6–73.9 19.3–19.8 76.3–76.7M. sacchariflorus 2.2–2.3 3.8–4.1 73.4–73.6 20.3–20.4 69.0–69.3M. sinensis 3.0–3.2 4.2–4.4 74.7–74.9 17.7–17.9 64.6–65.7*dry matter**dry matter ash-free basis407Babich O.O. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 403–411in the pharmaceutical industry. They can be used asantioxidant, antimicrobial, anti-inflammatory, anticancerbiological active substances for manufacturingdrugs to prevent HIV, thrombosis and atherosclerosis,reduce cholesterol, etc. [31, 32].Features of processing Miscanthus raw materialsfor energy industry products. Miscanthus is themain energy culture, because it has the most optimalflow ratio of in/out energy content parameters [33].Miscanthus as a lignocellulosic biomass with alow moisture content can be processed into fuelthermochemically. Figure 4 shows a simplified schemeof the two main ways of producing chemicals and fuelsfrom thermal conversion of miscanthus biomass [34].The first way is gasification, followed by Fischer-Tropsch synthesis, which requires large-scaleinstallations. Large-scale installations cannot be adaptedto biomass supply chain without biomass pyrolysisenergy compaction before its long range transport. Thesecond way is fast pyrolysis or biomass liquefaction,with the consequent quality biological oils increase inmodified refrigerators [35].Fast miscanthus pyrolysis was investigated ina fluidised bed reactor for production of bio-oildepending on the temperature (350–550°C), particle size(0.3 mm–1.3 mm), feed rate and gas flow rate. Thehighest bio-oil yield of 69.2% was observed at thetemperature of 450°C. With increasing temperature theamount of oxygenates in bio-oil gradually decreased,and the amount of water and aromatics increased. Theoutput of the bio-oil did not depend on particle size orfeed speed. The use of gaseous products as a mediumfor fluidisation increased the yield of bio-oil. It was alsoshown that partial removal of sodium and potassiumincreases the yield of Miscanthus × giganteus volatilesubstances due to the formation of semi-coke [36].Miscanthus gasification study was carried out ina fluidised layer using olivine as the primary catalyst.It was shown that miscanthus raw material producesabout 1.1 m3/kg gas containing more than 40% of H2 and24% CO. Gas outlet and H2 concentration increase withtemperature while the yields of tar, semi-coke, CO, CO2and CH4 decrease.Experiments on miscanthus gasification were carriedout in a circulating fluidised bed in the presence ofoxygen, magnesite or olivine as a granular catalyst andkaolin as the additive to reduce agglomeration of thelayer. Alkaline elements, mainly Na, K and Cl in theash of miscanthus lead to agglomeration of the silicarichmaterial in the fluidised bed. The use of magnesiteas an additive or as a bed material leads to a significantincrease in the hydrogen fraction volume in the gaseousproduct. Its maximum volume fraction can reach upto 40% during the gasification of biological materialwith a layer of magnesite. Magnesite has also shownexcellent results in resin content reduction and increasein hydrogen/carbon dioxide ratio (H2:CO).Thus, the analysis of scientific literature confirmsthe prospects of miscanthus as a source of energy. It canbe briquetted or granulated. Combusted pellets fromraw materials of miscanthus (Miscanthus × giganteus)demonstrated that the energy value of this productreaches 29 kJ/g. Meanwhile, low-temperature slowpyrolysis is energetically more favourable [37].Features of processing plant biomass tobioethanol. The use of lignocellulosic biomass as asource of raw materials for the production of bioethanolhas some complications, lying in its complex structure.It is established that the necessary preliminary chemicaltreatment of raw materials is needed. The processof raw materials bioconversion into bioethanol mayinclude both separate hydrolysis and fermentation andsimultaneous saccharification and fermentation, known,scientifically, as SHF and SSF processes, respectively.One of the main advantages of SHF is the ability ofenzyme preparations and microorganisms to operateunder their optimal conditions. However, a disadvantageof stages continuous implementation is excessive length.For the purposes of optimisation, today the consistentprocess is faced with an alternative of SSF.The advantage of this process is the carryingoutof saccharification and fermentation in oneFigure 4 Simplified scheme of fuel and chemicals productionMiscanthusbiomassPyrolysisLiquid-phasepretreatmentGasificationLiquefaction(> 5 МPа H2)Fast pyrolysisUpdateJointExtracts processing(chemicals)TheFischer-TropschProcessCrude oilFT ProductsCO, H2and/orFuelChemicalsubstancesCO,H2bio-oil408Babich O.O. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 403–411reactor, shortening time process steps and reductionin energy consumption. It is also known that in thesimultaneous process with introduction of bioethanolproducers reducing substances begin to escape fromthe system, getting used for the synthesis of bioethanol.Thus, the equilibrium of the cellulose hydrolysisenzymatic reaction is continuously shifted toward theformation of reaction products (glucose), achievingsaccharification intensification. However, one of thedrawbacks of the simultaneous method is the differencein optimum temperatures needed for enzyme activity atsaccharification stage (45–50°C) and for microorganismscultivation (28–30°C) [9].The main bioethanol producer in Russia is theyeast Saccharomyces cerevisiae, used in ethyl alcoholproduction both on food raw materials and hydrolysismedia. In some sources these microorganisms areconsidered as bioethanol producers on hydrolysates ofvarious types obtained from miscanthus raw materials.For example, the paper by Baibakova shows thescheme of obtaining ethanol as a result of bioconversionusing Saccharomyces serevisiae RNCIM Y-1693,isolated from the reactor of Kotlas (Arkhangelsk region)pulp and paper mill [28]. The peculiarity of the strainis its resistance to harmful impurities of hydrolysates.Optimal conditions for the strain are the temperature of26–28°C and native active acidity of the extract of 4.5–4.7 pH. Earlier it was shown that this strain is resistantto lack of nutrients in the medium, products of itsown metabolism and media obtained from cellulosecontainingraw materials by enzymatic hydrolysis. Theraw material was subjected to preliminary chemicaltreatment by alkaline delignification, after which theproducts of alkaline delignification were converted intoa solution of monosaccharides by enzymatic hydrolysis.Further, bioethanol was synthesised on the obtainedmedia [29].Another paper provides information thatbioethanol is also obtained by converting the strainwith Saccharomyces cerevisiae Y-1693, but a solutionof nitric acid is used for pretreatment. In this case,bioethanol yield reached 70.9 % [28, 30, 31].The use of consortium for enzymatic hydrolysate ofmiscanthus cellulose based on Pachysolen tannophilusand Saccharomyces cerevisiae strains is also described.The yield of ethanol amount to 44 % for P. TannophilusRNCIM Y-1532 producer; to 62.5% for S. сerevisiaeRNCIM Y-1693 of theoretically possible. With thecombined use of cultures, the rate of fermentationincreases by 10% compared to S. cerevisiae RNCIMY-1693, but there is no increase in the proportion ofethanol yield. Joint use of strains was consideredinappropriate [28, 31].Bioconversion by enzyme preparations incombination with hydrolysis by dilute nitric acid at90–96°C or alkaline delignification by 4% sodiumhydroxide solution at 90–96°C is used for pretreatmentof raw materials from miscanthus plants. Preparations‘Cellolux-A’ (Sibbiopharm Ltd, Berdsk) and ‘BruzimeBGX’ (Polfa Tarchomin Pharmaceutical Works S. A.,Poland) are used as cellulolytic enzymes.‘Cellolux-A’ is positioned in the market as cellulasefor non-starch polysaccharides fermentation, ‘BruzimeBGX’ – as hemicellulase [38]. As a result of enzymaticmethods of miscanthus raw materials hydrolysis,bioethanol with a low content of ethers and fusel oilswas obtained. There is no methanol in bioethanolobtained from miscanthus. However, saccharomycetesdo not ferment pentoses, whose amount in hydrolysatescan be significant (depending on the type of raw materialand the method of hydrolysate obtaining), into ethanol.Several types of yeast are known to ferment xylose intoethanol: Pachysolen tannophilus, Candida shehatae,Candida tropicalis, Pichia stipitis, etc. To select abioethanol producer, it is necessary to determine thespecific rate of yeast biomass growth and the rate ofsubstrate utilisation on synthetic media.In addition to the use of wild strains, work isunderway to obtain recombinant ones with increasedcapacity for bioconversion of raw materials. Thus, thepatent CN 106701605 Huazhong Agricultural Universitypresents a modified Saccharomyces cerevisiae SF4 yeastfor efficient ethanol fermentation using xylose [32].Specifics of processing plants into products forthe chemical and microbiological industry. Besidethe process of converting miscanthus raw materials toproduce biofuels, a large amount of research is devotedto the production of cellulose fibres. Cellulose is widelyused in modern industry, e.g. as a tablet excipient inpharmaceuticals, for the manufacture of fabrics, paper,plastics, explosives, etc.The paper by Gismatulina describes obtainingcellulose from miscanthus of Soranovski variety(Miscanthus sinensis Andersson) by the nitrate methodfeaturing two consecutive stages of processing thecrushed material with diluted solutions of nitric acid,then sodium hydroxide [33].The cellulose obtained by the nitrite method ischaracterised by high quality: the mass fraction ofα-cellulose is 96.1%, the degree of polymerisation is 970,the ash content and mass fraction of lignin are 0.11 and0.65%, respectively, the mass fraction of pentosans is0.8%. Miscanthus cellulose is similar in quality to cottoncellulose. With these parameters, it can be successfullyused for the synthesis of cellulose ethers and othervaluable products.In another paper, miscanthus samples are cellulosefrom the leaf and stem of miscanthus obtained separatelyby two methods (nitrite and combined) [34]. The nitritemethod consists in cooking raw material in a dilutesolution of nitric acid at atmospheric pressure, followedby treatment with a dilute solution of sodium hydroxide.Thus, cellulose obtained from the stem by the nitritemethod has a better quality than that from the leaf. Thisis reflected in high values of α-cellulose content (94.4%vs. 91.7%) and degree of polymerisation (800 vs. 580),and also low values of noncellulosic compounds mass409Babich O.O. et al. Foods and Raw Materials, 2019, vol. 7, no. 2, pp. 403–411fraction: ash – 0.07% vs. 1.01%, acid-insoluble lignin –0.45% vs. 1.51%.Celluloses obtained by the combined methoddemonstrate the same regularity: cellulose from the stemis characterised by higher quality than that from theleaf. The data show high value of polymerization degree– 1040 vs. 640 and low noncellulosic compounds massfraction: ash – 0.14% vs. 0.75%, acid-insoluble lignin– 0.88% vs. 4.12%, pentosans – 6.38% vs. 8.53%. Thecellulose obtained by the nitrite method may be suitablefor chemical modifications, including nitration. Thecellulose obtained by the combined method can be usedin paper industry [31].The use of miscanthus as a medium for bacteriacultivation can be carried out without the targetedproduction of simple sugars for use in the food, feedand pharmaceutical industries, as well as a substrate forbacterial growth. Some studies on bacterial cellulosesproduction present media based on incompletemiscanthus hydrolysates.Thus, Gladysheva describes obtaining bacterialcellulose by bioconversion of Medusomyces giseviibacteria on a synthetic nutrient medium, includingsucrose, black tea extract, starch hydrolysate, enzymaticmiscanthus hydrolysate [35]. Cultivation was carried outin static conditions at 25–29°C for 13 days.Gismatulina also used miscanthus raw materialsto obtain a nutrient medium for the growth of bacteriaproducing bacterial cellulose [36, 37]. Pre-hydrolysiswas carried out with 0.2% solution of nitric acid at 90–95°C for 1 h. Nitric acid treatment was carried out with4% nitric acid solution at 90–95°C for 6 h. Washingwas performed successively with 1% sodium hydroxidesolution, and then 1 % nitric acid solution. The resultingpulp was pressed with a vacuum filter, washed to aneutral reaction of washing water, dried to a moisturecontent of 7–10 %.The raw material for the experiments was groundto a particle size of 10–15 mm. It was established thatoptimal conditions of the principal and longest stage ofobtaining cellulose by the combined method (alkalinetreatment) are: sodium hydroxide concentration,4%; temperature, 90–98°C; duration, 6 h. Celluloseextraction under such conditions allows obtainingthe maximum yield of the target product – 35–40%with α-cellulose content of 87.0–90.3%, degree ofpolymerisation 950–990, residual lignin content of 2.0 to3.0%, ash content of 0.3–0.4%, and pentosan content of3.0 to 8.0%.Cellulose isolated from miscanthus by the combinedmethod is a promising substrate for enzymatichydrolysis, with the degree of its conversion was 91–93%by weight of the substrate. High quality indicators of thesubstrate allow predicting the effectiveness of its use forthe subsequent bacterial cellulose biosynthesis.Also miscanthus raw materials can provide organicacids, alcohols and adsorbents. The paper describesobtaining formic acid from lignocellulose or its majorcomponents, which comprises two successive stages:– acid-catalysed depolymerisation (polysaccharideshydrolysis, delignification);– subsequent monomers (monosaccharides, phenolicderivatives) oxidation into formic acid. A high yield offormic acid equal to 45% was obtained [23].Organosolv method of cooking miscanthus rawmaterials can also deliver ferulic, vanilla and paracumaricacids, sterines, among which the main factionsare β-sitosterol, 7-oxo-β-sitosterol, stigmasterol andcampesterol. However, this method has not becomewidespread, as sterol derivates are oxidized duringpreliminary treatment with organic solvents.CONCLUSIONFurthering lignocellulose biomass integratedprocessing by chemical and/or biotechnologicalmethods into a range of competitive products andenergy is a modern and fundamental area of industrialbiotechnology developing in industrial countries.The conducted botanical properties analysisof chemical composition and modern methods ofprocessing miscanthus species biomass proved thatit was a promising renewable wood-substituting rawmaterial for products of chemical, fuel, energy, andmicrobiological industries. Further research will focuson the selection of rational parameters of processingmiscanthus biomass into valuable products withimproved physical and chemical characteristics, suchas bio-ethanol, pellets, technical cellulose, bacterialcellulose, and carbohydrate-containing substrate.CONFLICT OF INTERESTThe authors declare no conflict of interest.FUNDINGThe survey lies within a framework of fundamentalresearch project No. 19-416-390001 ‘Scientific andtechnological foundations of Miscanthus plants biomassprocessing into products for the fuel and energy,chemical and microbiological industry’.