This paper reports new results on the synthesis and comparative characterization of cellulose nitrates (CNs) derived from Miscanthus × giganteus stems and from commercial microcrystalline cellulose (MCC). Miscanthus CNs synthesized by nitration with mixed sulfuric-nitric acids containing 16-20% water exhibit new functional properties: a high solubility in organic solvents (100% in acetone and 97-99% in alcohol-ether solvent) and a high viscosity (17-51 mPa·s), with a nitrogen content of 10.54-12.08 wt%. CNs from Miscanthus × giganteus are similar in nitrogen content and solubility to those from MCC (11.54% and 99%) but have a significantly greater viscosity (3 mPa·s), which is an undoubted advantage and considerably expands their potential application range. The solubility test of CNs synthesized from both sources demonstrated that Miscanthus CNs have a better film-forming ability. SEM analysis revealed a great difference in fiber length, despite the same cylindrical shape and observed aggregation: 1.0-2.0 mm for CNs from Miscanthus versus 40-60 μm for CNs from MCC. IR spectra of CNs from both sources showed the appearance of five new characteristic frequencies (1632-1633, 1273-1274, 823-826, 748, 677-686 cm-1 for Miscanthus CNs and 1659, 1277, 832, 747, 691 cm-1 for CNs from MCC), allowing the obtained compounds to be identified as nitric acid esters of cellulose. According to TGA/DTA analysis, the synthesized polymers have similarly high values of the onset temperature of both intense decomposition (197-198 °C) and narrow exothermic peaks (209-211 °C and 212 °C), respectively, indicating their high thermal stability. The combination of high solubility, viscosity, thermal stability and chemical purity of CNs derived from Miscanthus × giganteus stems suggests that strong thin films can be obtained and recommended for use in the manufacture of nitrocellulose membranes.

To avoid dependence on conventional raw materials, global emphasis has been placed on obtaining alternative plant celluloses and the chemical synthesis of cellulose. The use of synthetically derived cellulose as a precursor for cellulose nitrates (NCs) is currently absent in global practice, which underscores the undoubted relevance of this research. Cellulose nitrate (NC) was synthesized in a 138% actual yield by nitration of synthetic cellulose (SC)-a new type of cellulose-prepared by electropolymerization from an aqueous glucose solution in the presence of catalytic tungsten-vanadium heteropolyacid of the 1-12 series with the chemical formula H6[PW10V2O40]: a nitrogen content of 11.83%, a viscosity of 198 mPa·s, a high solubility of 91% in an alcohol-ether solvent, and an ash content of 0.05%. SEM provided a general concept of the morphological structure of SC and SC-derived NC. The initial SC consisted of flat, curly fibers with a smooth surface approximately 10-20 μm wide, with no aggregation observed. The fibers of SC-derived NC had a cylindrical shape with a diameter of up to 25 μm and a rough surface. FT-IR spectroscopy revealed that SC and SC-derived NC have the main functional groups characteristic of classical cellulose (3346, 2901, 1644, 1429, 1162, and 1112 cm-1) and nitrate esters of cellulose (1650, 1278, 832, 747, and 689 cm-1), respectively. For the first time, a full-profile analysis discovered that SC is made up of the monoclinic phase of cellulose Iβ with an antiparallel chain arrangement. SC with a crystallinity index (CrI) of 81-86% was shown to undergo amorphization upon nitration, with the CrI declining to 17% and the crystallite sizes decreasing from 44 × 62 × 59 × 94 Å to 29 × 62 × 26 × 38 Å. Coupled TGA/DTA revealed that SC exhibits a high-temperature endothermic peak of decomposition of 374 °C, with a weight loss of 84%. The thermostable SC-derived NC exhibits a high onset temperature of intense decomposition of 200 °C and an exothermic peak of 208 °C, with a weight loss of 88%, and is characterized by a high specific heat of decomposition of 7.74 kJ/g. This study provides new insights into the functionalization of SC with a high degree of polymerization, expanding the classical concepts of cellulose nitration.

Miscanthus is recognized as a priority feedstock for sustainable bioeconomy. However, the technological and environmental aspects of biotechnological transformation of Miscanthus remain understudied. In this work, a complete cycle of transformation of Miscanthus into bacterial nanocellulose, bioethanol and lactic acid was carried out, and the yields of the bio-based products from 1 ton of the feedstock and sustainability factors of production were estimated for the first time. Miscanthus giganteus from the Russian selection (the Kamis variety) was used as the feedstock. The complete cycle of biotechnological transformation of Miscanthus involved pretreatment with dilute solutions of nitric acid and/or sodium hydroxide at atmospheric pressure, followed by enzymatic hydrolysis of the resultant substrates (4 substrates, 4 initial concentrations) and subsequent fermentation of the said bio-based products on Miscanthus-derived nutrient media. The one-stage pretreatment with a dilute nitric acid solution, which allows a 12-40 % increase in the yield compared to the other pretreatments, was found to be a priority one for all the three bioproducts. It was found that 3.550 tons of bacterial nanocellulose or 0.156 tons of bioethanol, or 0.145 tons of lactic acid could be obtained from 1 ton of Miscanthus giganteus. The sustainability factor was shown to be well below 1.0 (ranging from 0.04 to 0.48) for all bioproducts, meeting the requirements of bioeconomy. The production of bacterial nanocellulose is the most promising in terms of the yield and pricing.

Both annual (cotton, flax, hemp, etc.) and perennial (trees and grasses) plants can serve as a source of cellulose for fiber production. In recent years, the perennial herbaceous plant miscanthus has attracted particular interest as a popular industrial plant with enormous potential. This industrial crop, which contains up to 57% cellulose, serves as a raw material in the chemical and biotechnology sectors. This study proposes for the first time the utilization of miscanthus, namely Miscanthus Giganteus “KAMIS”, to generate spinning solutions in N-methylmorpholine-N-oxide. Miscanthus cellulose’s properties were identified using standard methods for determining the constituent composition, including also IR and atomic emission spectroscopy. The dry-jet wet method was used to make fibers from cellulose solutions with an appropriate viscosity/elasticity ratio. The structural characteristics of the fibers were studied using IR and scanning electron microscopy, as well as via X-ray structural analysis. The mechanical and thermal properties of the novel type of hydrated cellulose fibers demonstrated the possibility of producing high-quality fibers from miscanthus.

This study is focused on exploring the feasibility of simultaneously producing the two products, cellulose nitrates (CNs) and bacterial cellulose (BC), from Miscanthus × giganteus. The starting cellulose for them was isolated by successive treatments of the feedstock with HNO3 and NaOH solutions. The cellulose was subjected to enzymatic hydrolysis for 2, 8, and 24 h. The cellulose samples after the hydrolysis were distinct in structure from the starting sample (degree of polymerization (DP) 1770, degree of crystallinity (DC) 64%) and between each other (DP 1510–1760, DC 72–75%). The nitration showed that these samples and the starting cellulose could successfully be nitrated to furnish acetone-soluble CNs. Extending the hydrolysis time from 2 h to 24 h led to an enhanced yield of CNs from 116 to 131%, with the nitrogen content and the viscosity of the CN samples increasing from 11.35 to 11.83% and from 94 to 119 mPa·s, respectively. The SEM analysis demonstrated that CNs retained the fiber shape. The IR spectroscopy confirmed that the synthesized material was specifically CNs, as evidenced by the characteristic frequencies of 1657–1659, 1277, 832–833, 747, and 688–690 cm−1. Nutrient media derived from the hydrolyzates obtained in 8 h and 24 h were of good quality for the synthesis of BC, with yields of 11.1% and 9.6%, respectively. The BC samples had a reticulate structure made of interlaced microfibrils with 65 and 81 nm widths and DPs of 2100 and 2300, respectively. It is for the first time that such an approach for the simultaneous production of CNs and BC has been employed.

Carbon neutrality is a requisite for industrial development in modern times. In this paper, we review information on possible applications of polymers from the energy crop Miscanthus in the global industries, and we highlight the life cycle aspects of Miscanthus in detail. We discuss the benefits of Miscanthus cultivation on unoccupied marginal lands as well as the rationale for the capabilities of Miscanthus regarding both soil carbon storage and soil remediation. We also discuss key trends in the processing of Miscanthus biopolymers for applications such as a fuel resources, as part of composite materials, and as feedstock for fractionation in order to extract cellulose, lignin, and other valuable chemicals (hydroxymethylfurfural, furfural, phenols) for the subsequent chemical synthesis of a variety of products. The potentialities of the biotechnological transformation of the Miscanthus biomass into carbohydrate nutrient media and then into the final products of microbiological synthesis are also examined herein.

Miscanthus is a valuable renewable feedstock and has a significant potential for the manufacture of diverse biotechnology products based on macromolecules such as cellulose, hemicelluloses and lignin. Herein, we overviewed the state-of-the art of research on the conversion of miscanthus polymers into biotechnology products comprising low-molecular compounds and macromolecules: bioethanol, biogas, bacterial cellulose, enzymes (cellulases, laccases), lactic acid, lipids, fumaric acid and polyhydroxyalkanoates. The present review aims to assess the potential of converting miscanthus polymers in order to develop sustainable technologies.

On the basis of X-ray diffraction experiment data the atomic molecular configuration in the short-range order region of amorphous nitrocellulose from Miscanthus is constructed by the computer simulation technique using the HyperChem 8 program. It is shown that the arrangement of atoms in the short-range order region of amorphous nitrocellulose is satisfactorily described by a cluster composed of nine nitrocellulose chains, two cellulose I chains twisted by an angle of 72°, and two untwisted cellulose I chains. Each chain contains ten glucose residues. In the final cluster, the above-mentioned chains form an approximately hexagonal layer in projection on plane ab with a distance between them being 12.2 Å. In projection on plane bc , the dimensions of the final cluster are 28 Å along axis b and 54 Å along axis c . The total number of atoms is 3300, and the degree of polymerization is 130; the formula unit of the asymmetric fragment is [C 6 H 7.24 O 2 (OH) 0.92 (ONO 2 ) 2.08 ] 130 . The result reliability is proved by the fact that the experimental curve of X-ray scattering intensity distribution I ( s ) and the corresponding curve calculated for the cluster coincide with an accuracy of up to 7.5%.

The global abundance and availability of oat hulls make them a promising feedstock to produce a unique type of cellulose, the bacterial one. This is the first study examining how a chemical pretreatment method of oat hulls influences the yield and properties of bacterial cellulose (BC) in extended cultivation. Here we employed our own pretreatment methods that use dilute HNO3 and NaOH solutions in one and two stages, a total of four pretreatment methods. Further technological stages were performed in the same manner: pulps were enzymatically hydrolyzed with commercial enzymes CelloLux-A and BrewZyme BGX, and biosynthesis of BC was run using the Medusomyces gisevii Sa-12 symbiotic culture. A two-stage (HNO3 + NaOH) pretreatment of oat hulls was found to afford a biologically good medium and increase the BC yield 1.8−3.2-fold compared to the other pretreatments used. A pretreatment method of oat hulls determined the BC yield and degree of polymerization. However, a pretreatment method had no impact on the highest crystallinity index and allomorph Iα content of all the BC samples, which is explained by Medusomyces gisevii Sa-12 used. The crystallinity index and allomorph Iα content, as measured by X-ray diffractometry, are proposed for use as BC quality assessment criteria.

Lignocellulosic biomass is of great interest as an alternative energy resource because it offers a range of merits. Miscanthus × giganteus is a lignocellulosic feedstock of special interest, as it combines a high biomass productivity with a low environmental impact, including CO2 emission control. The chemical composition of lignocellulose determines the application potential for efficient industrial processing. Here, we compiled a sample collection of Miscanthus × giganteus that had been cultivated in different climate regions between 2019 and 2021. The chemical composition was quantified by the conventional wet methods. The findings were compared with each other and with the known data. Starting as soon as the first vegetation year, Miscanthus was shown to feature the following chemical composition: 43.2–55.5% cellulose content, 17.1–25.1% acid-insoluble lignin content, 17.9–22.9% pentosan content, 0.90–2.95% ash content, and 0.3–1.2% extractives. The habitat and the surrounding environment were discovered herein to affect the chemical composition of Miscanthus. The stem part of Miscanthus was found to be richer in cellulose than the leaf (48.4–54.9% vs. 47.2–48.9%, respectively), regardless of the planation age and habitat. The obtained findings broaden the investigative geography of the chemical composition of Miscanthus and corroborate the high value of Miscanthus for industrial conversion thereof into cellulosic products worldwide.

A chemical composition assessment was performed on a industrial crop in Russia, Miscanthus Ч giganteus harvested in 2019–2021. It was found that, regardless of the habitat, after the second year of vegetation, Miscanthus Ч giganteus has a cellulose content exceeding 50 %, which makes it a cellulose-based material. The positive impact of Miscanthus Ч giganteus on the environment was demonstrated. Cultivation of Miscanthus Ч giganteus regulates CO2 exchange, and its processing into cellulose, biofuels and high-tech products will reduce deforestation.

Miscanthus, which can grow on marginal lands and capture CO2, has great potential as an industrial crop. A complete cycle to convert Miscanthus sacchariflorus, grown in Western Siberia (Russia), into bioethanol has successfully been implemented on a pilot scale and employed in downstream ethylene production for the first time. The Miscanthus bioprocessing technology involved mechanical comminution; HNO3-pretreatment; hydrolysis with commercial enzyme preparations CelloLux-A and BrewZyme BGX with cellulase-glucanase-xylanase action; pre-saccharification with substrate feed; simultaneous saccharification and fermentation with delayed inoculation (dSSF) with non-GMO Saccharomyces cerevisiae Y-1693 supplemented with or without (NH4)(2)SO4, KH2PO4 and yeast extract; rectification; and alumina-catalyzed dehydration to ethylene. Here we discussed pulp reactivity, yield and composition of Miscanthus products at each step (including ethylene), and compared the quality of the bioethanol obtained in the study with published data. The pulp feeding from 80 to 100 g/L resulted in a bioethanol concentration of similar to 40 g/L. It is the HNO3 pretreatment that provided pure bioethanol with an impurity content as low as 6.5 g/L. Bioethanol (92%-w) contained similar to 0.85 g/L impurities, mainly n-propanol and isobutanol; the latter weakly influenced the catalyst activity in ethylene production. The supplement slightly increased the yields of bioethanol and fusel alcohols, thereby reduced the yield of byproducts and improved the ethylene quality. The achieved yields of bioethanol and ethylene were 260 L/ton and 115 kg/ton Miscanthus, respectively. The expected yield of absolute ethylene under pilot-scale conditions can be 122 kg/ton Miscanthus.

The results of X-ray diffraction analysis of bacterial nanocellulose (BNC), synthesized by Komagataeibacter xylinus В-12429 and Komagataeibacter xylinus В-12431 producers in enzymatic hydrolyzates of miscanthus, oat hull, and synthetic nutrient medium, are presented. It is found by full-profile analysis that the dominant component in all BNC samples studied, independent of the producer and nutrient medium, is allomorph Іα, whose content varies from 96 to 100%. The following characteristics of the supramolecular structure of the samples have been determined: the degree of crystallinity, sizes of elementary fibrils and the shape of their cross section, and the coherence length of elementary fibrils along the fibril axis.

Extended cultivation with multiple removal of BC pellicles is proposed herein as a new biosynthetic process for bacterial cellulose (BC). This method enhances the BC surface area by 5–11 times per unit volume of the growth medium, improving the economic efficiency of biosynthesis. The resultant BC gel-films were thin, transparent, and congruent. The degree of polymerization (DP) and elastic modulus (EM) depended on the number of BC pellicle removals, vessel shape, and volume. The quality of BC from removals II–III to VII was better than from removal I. The process scale-up of 1:40 by volume increased DP by 1.5 times and EM by 5 times. A fact was established that the symbiotic Medusomyces gisevii Sa-12 was adaptable to exhausted growth medium: the medium was able to biosynthesize BC for 60 days, while glucose ran low at 24 days. On extended cultivation, DP and EM were found to decline by 39–64% and 57–65%, respectively. The BC gel-films obtained upon removals I–VI were successfully trialed in experimental tension-free hernioplasty.

Bacterial nanocellulose (BNC) is a unique product of microbiological synthesis, having a lot of applications among which the most important is biomedicine. Objective complexities in scaling up the biosynthesis of BNC are associated with the nature of microbial producers for which BNC is not the target metabolite, therefore biosynthesis lasts long, with the BNC yield being small. Thus, the BNC scale-up problem has not yet been overcome. Here we performed biosynthesis of three scaled sheets of BNC (each having a surface area of 29,400 cm2, a container volume of 441 L, and a nutrient medium volume of 260 L and characterized them. The static biosynthesis of BNC in a semisynthetic nutrient medium was scaled up using the Medusomyces gisevii Sa-12 symbiotic culture. The experiment was run in duplicate. The BNC pellicle was removed once from the nutrient medium in the first experiment and twice in the second experiment, in which case the inoculum and glucose were not additionally added to the medium. The resultant BNC sheets were characterized by scanning electron microscopy, capillary viscosimetry, infrared spectroscopy, thermomechanical and thermogravimetric analyses. When the nutrient medium was scaled up from 0.1 to 260 L, the elastic modulus of BNC samples increased tenfold and the degree of polymerization 2.5-fold. Besides, we demonstrated that scaled BNC sheets could be removed at least twice from one volume of the nutrient medium, with the yield and quality of BNC remaining the same. Consequently, the world's largest BNC sheets 210 cm long and 140 cm wide, having a surface area of 29,400 cm2 each (weighing 16.24 to 17.04 kg), have been obtained in which an adult with burns or vast wounds can easily be wrapped. The resultant sheets exhibit a typical architecture of cellulosic fibers that form a spatial 3D structure which refers to individual and extremely important characteristics of BNC. Here we thus demonstrated the scale-up of biosynthesis of BNC with improved properties, and this result was achieved by using the symbiotic culture.

The study was performed for miscanthus introduced and grown in West Siberia. Transformation of miscanthus into bacterial nanocellulose was accomplished for the first time. The microbiological synthesis of bacterial nanocellulose using the Medusomyces gisevii Sa-12 symbiotic culture gave chemically pure bacterial nanocellulose with exceptionally high crystallinity index and content of Iα allomorph.

One of the ways to enhance the yield of bacterial cellulose (BC) is by using dynamic aeration and different-type bioreactors because the microbial producers are strict aerobes. But in this case, the BC quality tends to worsen. Here we have combined static culture with aeration in the biosynthesis of BC by symbiotic Medusomyces gisevii Sa-12 for the first time. A new aeration method by feeding the air onto the growth medium surface is proposed herein. The culture was performed in a Binder-400 climate chamber. The study found that the air feed at a rate of 6.3 L/min allows a 25% increase in the BC yield. Moreover, this aeration mode resulted in BC samples of stable quality. The thermogravimetric and X-ray structural characteristics were retained: the crystallinity index in reflection and transmission geometries were 89% and 92%, respectively, and the allomorph Iα content was 94%. Slight decreases in the degree of polymerization (by 12.0% compared to the control―no aeration) and elastic modulus (by 12.6%) are not critical. Thus, the simple aeration by feeding the air onto the culture medium surface has turned out to be an excellent alternative to dynamic aeration. Usually, when the cultivation conditions, including the aeration ones, are changed, characteristics of the resultant BC are altered either, due to the sensitivity of individual microbial strains. In our case, the stable parameters of BC samples under variable aeration conditions are explained by the concomitant factors: the new efficient aeration method and the highly adaptive microbial producer―symbiotic Medusomyces gisevii Sa-12.

МИНИСТЕРСТВО НАУКИ И ВЫСШЕГО ОБРАЗОВАНИЯ РФБийский технологический институт (филиал) федерального государственного бюджетного образовательного учреждения высшего образования «Алтайский

Due to the limited volumes of conventional sources of cellulose (cotton and wood), research centered on producing the most competitive science-driven products – cellulose nitrates – from new, domestic, easily renewable feedstocks is extremely relevant. The review of scientific literature corroborates the lack of data on the feasibility to obtain cellulose nitrates from Miscanthus, except for the authors’ publications. Here we suggest a tree-like industrial crop, Miscanthus var. KAMIS, growing with an yield of up to 20 t/ha a year on industrial plantations in Kaliningradskaya, Kaluzhskaya and Yaroslavskaya Oblasts and in Primorskiy Krai. A pulp sample derived from Miscanthus var. KAMIS by the nitric-acid process exhibits a high α-cellulose content of 96 % and degree of polymerization of 1350. Under optimum synthesis conditions previously identified for unconventional feedstocks, a cellulose nitrate sample was synthesized by treating the pulp with commercially available mixed acid and had the following functional characteristics: 11.26 % nitrogen content, 52 mPа∙s viscosity, and – 95 % solubility on alcohol-ester mixture. Morphological features of pulp and cellulose nitrate samples were characterized by scanning electron microscopy. IR spectroscopy revealed the presence of functional groups in pulp samples (3411, 2913, 1637, 1429, 1369, 1317, 1161, 700-500 cm-1) and cellulose nitrate samples (2553, 1642, 1276, 830, 746, 680 cm-1), which allow those samples to be identified as cellulose and nitrate cellulose esters, respectively. It was found by scanning electron microscopy that the cellulose nitrate sample matches industrial Colloxylines by the onset temperature of decomposition (199 °С) and specific head of decomposition (8,43 kJ/g). The practical importance of this study is that we experimentally justify the feasibility to utilize the new, unconventional, domestic, easily renewable feedstock, Miscanthus var. KAMIS, as a precursor of high-quality cellulose nitrates

The demand for precursors obtained by biotechnological means is constantly growing in technical chemistry. The use of bioethanol is therefore of interest in the production of ethylene. In this work, Miscanthus sacchariflorus is used as a raw material for the production of bioethanol for the first time. The stage of the chemical treatment of miscanthus with 4 wt % nitric acid solution is successfully scaled-up under the conditions of pilot industrial production, and the products of nitric acid treatment (PNTs) are obtained with a yield of 37.4% and a 96.0% content of hydrolyzable components. It is shown that preliminary chemical treatment of miscanthus with nitric acid, regardless of its type, allows substrates with similar chemical compositions to be obtained. The process is scaled up for the first time in a fermenter with a capacity of 11 L (a scaling factor of 1 : 8) to combine the saccharification and fermentation of PNTs from miscanthus and raise the concentration of PNTs from 60.0 to 90.0 g/L. Commercially available enzyme preparations Cellolux-A and Bruzheim BGX are used for saccharification. Yeast strain VKPM Saccharomyces cerevisiae Y-1693 is used for fermentation. It is found that the concentration of bioethanol grows by 9.5 g/L upon raising the substrate concentration from 60.0 to 90.0 g/L. It is recommended that a substrate concentration of 90.0 g/L be used to scale up the process under trial industrial conditions. A basic scheme isproposed for producing bioethanol with a yield of bioethanol 202 L/t of miscanthus.