Products of reactions between L-ascorbic acid and various nitrogen-containing biologically active substances can be used to develop new preparations with promising applications in the pharmaceutical, food, and cosmetic industries. The present study examined the interaction of L-ascorbic acid with p-aminoacetanilide in ethanol medium at component ratios of 1:1 and 1:2. The target products were obtained by controlling the temperature of aqueous ethanol solutions containing the specified amounts of components (50 °С, 1 h), which was followed by slow solvent removal for 24 h. Immediately after the temperature control stage, the reaction systems, in the form of thin films on KBr substrates, were analyzed via vibrational spectroscopy. Following slow solvent removal, the solid phases washed with anhydrous ether and its mixture with ethanol were studied in a KBr matrix using infrared spectroscopy. The vibrational spectra of the 1:1 reaction system revealed that no ionic associate is formed during the temperature control stage; subsequent solvent removal leads to the release of the solid phase of co-crystallization product, whose formation is confirmed by analysis of the mid- and near-infrared spectra. With the 1:2 component ratio, the reaction system was found to form a Schiff base at the C 3 of ascorbic acid during the temperature control stage, which subsequently rearranged during slow solvent removal into a 3-substituted N-derivative of ascorbic acid (3-deoxy-3-(p-acetamidophenylamino)-L-ascorbic acid). The electronic spectra of both reaction systems indicate insignificant side processes of melanoidin formation under the selected experimental conditions. According to published sources, the structural analogs of released products are characterized by sufficient stability compared to aliphatic derivatives, as well as notable antioxidant properties, which indicates the importance of their further study.

Drugs and toxic compounds-induced liver and kidney injuries are mostly responsible for hepatic and renal dysfunction. Many treatments have recently been proposed for these injuries, like chemicals and traditional medicines. Thus, looking for new classes of natural and safe compounds is a global demand. The genus Salvia from the Lamiaceae family are well-studied and vastly used in traditional medicine. The plant contains a variety of secondary metabolites, like terpenoids, which have shown many pharmacological activities. Based on the various reported pharmacological effectiveness of Salvia officinalis L. (sage, I), the protective effects of some extracts and essential oil of this plant by the number of polar and nonpolar organic as well as aqueous solvents on the liver and kidney injury in acetaminophen-induced mice investigated in this research. The results showed that chloroformic and carbon tetrachloride extracts of Salvia officinalis had the best effects for protecting against kidney injury, while for liver, chloroformic, ethanolic, and hydroethanolic extracts also had such effects. It can be concluded that extraction of Salvia officinalis with polar and nonpolar organic and aqueous solvents could separate various bioactive components which appropriately and remarkably improve some serum markers following acetaminophen-induced liver and kidney damage in mice.

Psychrophilic and psychrotrophic microorganisms are widespread throughout the world and found in the depths of seas, lakes, and oceans, as well as in glaciers, polar regions, Arctic ice, caves, and on mountain peaks. Unlike their mesophilic and thermophilic counterparts, these microorganisms can survive in cold climates by expressing cold-adapted enzymes that have unique catalytic properties. Cold-active enzymes exhibit higher catalytic activity at low temperatures, structural flexibility of active sites, and thermolability. Due to the specified characteristics, these enzymes are becoming increasingly attractive for industrial use, as they can lower the energy costs of the reaction, decrease the number of side reactions, and are relatively easy to inactivate. In addition, increased structural flexibility can lead to broad substrate specificity, which expands their scope of application. Due to the relative simplicity of large-scale production (as compared to that of plant and animal enzymes), microbial enzymes are becoming increasingly attractive for commercial use, which contributes to the rapid development of the enzyme market. Cold-active enzymes can be used in various biotechnological and industrial processes: molecular biology, biotransformation, detergent production, food and beverage production, the textile industry, wastewater treatment, biocellulose production, environmental bioremediation in cold climates, etc. Of particular interest for various biotechnological processes are genetically modified strains producing certain types of cold-active enzymes. This article provides a review of several recent studies on the production of cold-active microbial enzymes and their application.

The study investigates the potential use of a biocomposite composed of bacterial cellulose and Debaryomyces hansenii yeast in enantioselective biocatalysis to produce enantiopure secondary alcohols. As a result of testing three strains of Debaryomyces hansenii yeast, it was determined that in the presence of an exogenous reducing agent (isopropanol), the biomass of strain D-43-1 reduces acetophenone enantioselectively to highly enantiopure S-1-phenylethanol (at least 99%). Cell immobilization of the Debaryomyces hansenii strain D-43-1 on a bacterial cellulose gel film yielded a biocomposite for the study of its effectiveness as a biocatalyst for acetophenone reduction or as an immobilized inoculum for the production of yeast biomass with carbonyl reductase activity. The use of biocomposite as a biocatalyst was found to be impossible: the product of acetophenone reduction was not detected in the reaction mixture. When used as an immobilized inoculum, biocomposite intensifies the production of enzymatically active yeast biomass suitable for the enantioselective reduction of acetophenone to enantiopure S-1-phenylethanol. The biomass yield achieved in the first fermentation cycle using the immobilized inoculant is three times higher than that produced using the planktonic inoculum. Four repeated fermentations during a 15-hour cell culture consistently achieve a biomass yield of approximately 13 g/L, which is almost twice the level achieved over the same period of time using planktonic inoculum. Biomass obtained using the biocomposite was shown to be reusable. At a biomass dry weight concentration of 40 g/L, the product yield consistently reaches 86–88% during the four transformation cycles, decreasing to 65% only in the fifth cycle.

The study aimed to demonstrate the sorption ability of Paracoccus yeei VKM B-3302 cells to remove palladium nanoparticles from aqueous media. An important feature of this study was the size distribution analysis of palladium nanoparticles depending on the method used to store Paracoccus yeei VKM B-3302 cells after culture. The average diameter of palladium nanoparticles formed with the use of native (non-frozen) microbial cells was found to be equal to 3.99±0.03 nm, whereas in the case of microorganisms frozen at temperatures of minus 4 °С and minus 20 °С, it increased to 4.3±0.1 and 4.5±0.6 nm, respectively. These observations highlight the important role of the viability of Paracoccus yeei VKM B-3302 cells in the formation and stabilization of palladium nanoparticles, as well as in the determination of their size characteristics. The produced biohybrid materials exhibit pronounced catalytic activity and can be effectively used in Mizoroki – Heck cross-coupling reactions, which confirms their high functional significance. It is assumed that the retention and stabilization of palladium nanoparticles are ensured by a complex of chemical interactions, including amide bonds in proteins and carboxyl and amino groups of amino acids, as well as glycosidic bonds in polysaccharides, lipids, and peptidoglycan, which are part of the cell envelope. These components create a multifunctional matrix that enables reliable fixation and activity of nanoparticles.

The study aimed to examine the effects of conditions for obtaining sodium alginate from the brown alga Fucus vesiculosus on the yield, molecular weight, and physicochemical and rheological properties of the polysaccharide, as well as to determine the levels of toxic elements in the obtained product to assess its potential use as a food additive. The extraction was performed under different time (1 and 5 hours) and temperature (25, 60, and 80 °С) conditions, with the use of different precipitants (C₂H₅OH and HCl). The viscosity-average molecular weight of sodium alginate was determined via capillary viscometry. The identification of samples was performed using Fourier transform infrared spectroscopy. The levels of toxic elements in the alga and sodium alginate were determined through inductively coupled plasma mass spectrometry. The rheological properties of aqueous sodium alginate solutions were studied using a method of shear rheology. The rheological curves were fitted with the Cross and Ostwald – de Waele models. A longer extraction time and a higher extraction temperature were found to increase product yield, molecular weight, and rheological properties, while lowering organoleptic properties. The sample obtained at extraction temperature and time of 25 °С and 1 hour, respectively (with the washing stage repeated five times and the centrifugation stage replaced with filtration), was characterized by the highest values of molecular weight (592 kDa) and rheological properties. Also, in terms of its properties, the obtained sample was superior to the commercial sample. It was shown that since the levels of toxic elements do not exceed the maximum permissible concentrations, sodium alginate can be used as a food additive.

Truffles (Tuber sp.) are among the rarest and most valuable fungi with high nutritional value and biotechnological potential. Truffle mycelium and fruiting bodies are rich in protein and can serve as a source of biologically active compounds. The present study was aimed at assessing the effect of a food supplement based on truffle fruiting bodies on the physiological and hematological parameters of laboratory rats. For the experiment, eighteen adult male Wistar rats were selected and divided into three groups. The control group received standard feed, while the two experimental groups received powdered truffle fruiting bodies or boiled chicken meat (20% of their daily ration) in addition to the cereal feed. Both experimental groups were subjected to moderate physical exertion via forced swimming. The experiment assessed changes in the body weight, grip strength, and hematological parameters of laboratory animals. The rats receiving a product based on powdered black truffle fruiting bodies showed positive changes in physiological and hematological parameters. Thus, the obtained results indicate the potential of truffles to serve as a functional dietary component that improves physical endurance and metabolic processes. The findings offer prospects for the development of dietary supplements and food products on the basis of truffles.

The study was aimed at evaluating the resistance of Alcaligenes faecalis 2, Achromobacter pulmonis, Paenibacillus odorifer, and Bacillus subtilis biofilms to negative physicochemical external factors during batch culture. The main analyzed parameters included temperature (10 and 50 °С) and pH level (5.0 and 10.0), as well as surfactant (sodium dodecyl sulfate) concentrations of 5, 10, and 50 mg/dm³. At low temperatures (10 °С), the size of Alcaligenes faecalis 2, Achromobacter pulmonis PNOS, and Bacillus subtilis biofilms was found to increase. The Alcaligenes faecalis 2 biofilm was noted to exhibit resistance and metabolic activity under acidic conditions. A pH rise to 10.0 resulted in a higher amount of Bacillus subtilis biofilm. When exposed to sodium dodecyl sulfate solution (5 to 10 mg/dm³), Alcaligenes faecalis 2, Bacillus subtilis, Achromobacter pulmonis PNOS, and Paenibacillus odorifer biofilms were observed to form. In response to the exposure to high sodium dodecyl sulfate concentrations (10 and 50 mg/dm³), the biomass and size of Achromobacter pulmonis PNOS biofilm remained unchanged. Thus, the considered cultures were shown to be stress-resistant to negative external factors, which may contribute to the resistance of microbial cultures to various types of pollutants in treatment technologies.

The study aimed to examine the effect of conditions for aqueous extraction from sawdust on the biological activity of extractive substances for test objects from different taxonomic and ecological groups: Pleurotus ostreatus 0482 basidiomycete, Bacillus bacteria, and radish Raphanus sativus (L.). The obtained solutions were found to inhibit the growth and development of most test objects in proportion to the extraction temperature (up to 40% for some indicators). In solid-state fermentation, the biological efficiency of Pleurotus ostreatus 0482 increased by 25–40% after removing water-soluble extractives. The extracts were fractionated with successive use of hexane and chloroform. For all organic and aqueous phases, absorption ultraviolet/visible spectra were obtained. A comparison of spectral characteristics revealed absorption maxima within the range of 200–300 nm. With rising extraction temperature, the number of peaks was observed to increase; a total of eight maxima was identified, including batho- and hypsochromic shifts of the same compound. A mathematical processing of the spectra revealed patterns linking spectral characteristics to the biological action of extracts. The conducted absorption maximum analysis indicates the presence of lignans as potential phytotoxins, as well as flavonoids and stilbenes as possible inducers of enzymatic activity. The study analyzed the assumed chemical nature of bioactive compounds, as well as examining possible mechanisms of their action and practical applications of the obtained results.

Betulin is a natural pentacyclic triterpenoid compound exhibiting a wide range of biological activity. The industrial use of betulin as a pharmaceutical substance requires addressing several key issues, including intensification of extraction from plant raw materials and improvement of its bioavailability. The present study was aimed at examining the effect of preliminary ultrasonic treatment of crushed birch bark on the efficiency of subsequent extraction and the characteristics of the target product. The conducted experiment shows that power optimization of ultrasonic treatment within the range of 250–300 W increases the yield of extractive substances to 37.0%; after the purification stage, the yield of the crystalline product (betulin) increases by 14.9% compared to the control sample (without ultrasonic treatment of phytomass), which in relative terms amounts to an excess of 43%. A comprehensive purity analysis of the obtained compound (thin-layer chromatography; infrared spectroscopy; melting temperatures of 257–259 °С) confirmed the high efficiency of the proposed purification method for removing related impurities and preserving the structural integrity of the target substance. Thus, the use of solvent extraction combined with the ultrasonic homogenization of birch bark phytomass increases the yield of the target high-purity product, as well as reducing the consumption of raw materials and extraction solvents. These advantages contribute significantly to efficient use of resources, which suggests that it is technologically and economically feasible to scale up this process.

Given the need to protect metal structures and equipment from the destructive effects of aggressive media, the search for new corrosion inhibitors constitutes a relevant and important area of development in the modern chemical industry. Corrosion significantly reduces the durability and reliability of metal products, which increases maintenance costs and the risk of failures, while also negatively affecting environmental safety. Therefore, it is relevant to synthesize compounds with potential anticorrosive properties. In order to expand the range of such substances, secondary amines were obtained by condensing cyclic aldehydes and primary amines, as well as by reducing condensation products. The structure of the synthesized compounds was confirmed via infrared spectroscopy and nuclear magnetic resonance spectroscopy (¹H and ¹³C). The infrared spectra of the synthesized azomethines reveal imine-characteristic C=N stretch absorption bands at 1650–1570 cm^-1. In the ¹H nuclear magnetic resonance spectra, the protons of the azomethine group resonate at 8.15–8.25 ppm; the ¹³C nuclear magnetic resonance spectra reveal the carbon atoms of the imine group at δ_c of 158.00–161.00 ppm. The ability of the obtained compounds to inhibit corrosion in a model medium was tested using a gravimetric method. Their protective properties were evaluated using an electrochemical method. The properties of the obtained compounds are consistent with data presented in bibliographic sources. The best result was obtained for the secondary amine 2-((2-((4-chlorobenzyl) amino)ethyl)amino)ethan-1-ol, which exhibits anticorrosive properties in a hydrogen sulfide medium and provides a 97% protection level.

The study aims to identify factors contributing to the development of various Russian industries that use supercritical fluid technologies and facilitate their transition from laboratory to industrial scale. The considered technologies are used in the pulp and paper, oil and gas, construction, woodworking, textile, automotive, food, chemical, agricultural, pharmaceutical, and space industries, as well as in medicine and ecology. The specifics of applying supercritical fluid technologies in these sectors are considered. Carbon dioxide is the most commonly used solvent due to its availability and relatively low critical parameters. Supercritical water and other fluids have prospects for industrial use; however, their use on an industrial scale requires thermodynamic conditions. Technological and industrial sovereignty is ensured by the resource capabilities of the oil and gas, food, and agricultural industries. Of strategic importance is the space industry, which requires further research into the application of supercritical fluid technologies. Some sectors of the Russian industry can contribute to sovereignty, provided that equipment is produced for applying promising technologies and expanding the range of various solvents on an industrial scale. It is also necessary to introduce a pilot stage between laboratory research into the application of supercritical fluid technologies and the transition to the industrial stage. For several industries, sovereignty requires a greater quantity of raw materials used in supercritical fluid systems. In conclusion, the identified factors are discussed from the perspective of the large-scale development of specific industries through the considered technologies.

Development of methods for converting agricultural waste into valuable chemical products constitutes an important task designed to improve the efficiency of natural resource use. A promising approach is microwave-assisted pyrolysis, which offers high heating rates, selective action, and potential for scaling. In order to implement microwave processing of oak wood, a specialized processing unit was developed; its key element is a microwave reactor with a capacity of up to 3 L. The present study compared the IR spectra of oak wood prior to and after exposure to microwave radiation, as well as that of the obtained gaseous fraction. The IR spectrum analysis of the original wood and the solid residue from pyrolysis revealed structural changes in the polymer components of wood (cellulose, lignin, and hemicelluloses), while the IR spectrum analysis of the gaseous fraction helped identify the main gaseous reaction products. In addition, an elemental analysis of oak wood and the solid product of its microwave processing was conducted. The obtained data indicate a decrease in H/C and O/C atomic ratios by 0.73 and 0.44, respectively, during wood pyrolysis. The estimated calorific value of the solid residue increased twofold, which suggests the potential of using pyrolysis products as fuel due to the increased energy value. The obtained results indicate the potential of microwave pyrolysis in the conversion of agricultural waste into high-carbon materials with increased calorific value.

Encapsulation of mineral fertilizers is one of the most effective ways to reduce nutrient losses. In order to obtain protective coatings on the surface of fertilizer granules, a wide range of natural and synthetic polymers is used. The main disadvantage of synthetic polymers lies in their accumulation in soil due to their inability to biodegrade. One way to ensure biodegradability is to use vegetable oil polymers as coating materials. The present study used linseed and tung oils, which were applied to the moving layer of granules in a pan granulator by means of a pneumatic atomizer. The protective coating was formed through the polymerization of oil directly on the particle surface. The process was accelerated via hot-air heating and the addition of a manganese drier to the oil. As a result, encapsulated carbamide samples with 7% and 10% coating contents were obtained. The study analyzed the kinetics of carbamide release from the obtained capsules in aqueous medium under static conditions. For both types of oil, the release curves are S-shaped. The duration of encapsulated fertilizer effect increases at a greater coating mass fraction and, therefore, capsule thickness. A comparative analysis showed that the barrier properties of tung oil-based coatings are significantly better than those of linseed oil-based coatings. At a capsule mass fraction of 10%, it takes 14 days for 80% of carbamide to be released in the case of linseed oil and 56 days in the case of tung oil, i.e., four times longer.

The study of volatile impurities in crude bioethanol is of great technical importance for further catalytic conversion of bioethanol to industrial chemicals, as well as of considerable significance in the prevention of potable alcohol adulteration. This study was the first to analyze volatile impurities in crude bioethanol obtained from giant miscanthus using three proprietary pretreatment methods. These methods are based on treating raw materials with dilute nitric acid solutions at atmospheric pressure. The classical method for the pretreatment of cellulose-containing non-wood raw materials – alkaline delignification with sodium hydroxide – was used as the reference method. The resulting substrates were subjected to enzymatic hydrolysis (using Cellolux-A and Ultraflo Core preparations) together with alcoholic fermentation (using Saccharomyces cerevisiae Y-3136). The composition of crude bioethanol was determined using gas-liquid chromatography. The methodology used to produce bioethanol provided a means to obtain crude bioethanol with a methanol content of no more than 0.009 vol%, which is ten times lower than that regulated by industry codes. The purity of crude bioethanol samples is determined by two parameters: first, the number of pretreatment stages (two-stage pretreatment reduces the total amount of impurities in crude bioethanol by 4–21 times compared to single-stage pretreatment); second, a specific method of single-stage pretreatment (for example, pretreatment with nitric acid yields crude bioethanol with five times higher purity than in the case of the classical alkaline delignification).