Oscillating chemical and biochemical reactions are of particular interest for understanding complex mechanisms underlying the evolution and self-organization of wildlife. Sustained oscillations (self-oscillations) are observed in a number of chemical and biological reactions: reactions of Belousov – Zhabotinsky (“bromate oscillators”), Briggs – Rauscher (“iodine clock”), Bray – Liebhafsky, liquid-phase oxidation of benzaldehyde, etc. In the ideal kinetics of the law of mass action, self-oscillations are described only by nonlinear mechanisms that can yield an unstable reaction. The present study aims to explore the possibility of describing self-oscillations in homogeneous chemical reactions proceeding according to linear mechanisms with nonideal kinetics. In the course of work, the qualitative theory of ordinary differential equations and numerical methods for their solution were used. The study considers homogeneous chemical reactions proceeding according to linear stepwise schemes with three or more reactants with nonideal Marcelin – de Donder kinetics in an open isothermal gradientless reactor. These reactions are shown to involve the self-oscillations of reactant concentrations and reaction rate, with varying periodicity and frequency. For these reactions, mathematical models were constructed to describe self-oscillations associated with deviations from the ideal kinetics of the law of mass action, taking the possible mutual influence of reactants into account. Examples are given of linear stepwise schemes based on the Brusselator, a classical model for chemical oscillations, and the butene isomerization reaction. An alternative explanation is proposed for the possible causes of self-oscillations: stable modes of homogeneous reactions are disrupted due to the nonideal kinetics, which enables the description of self-oscillations in such reactions by linear stepwise schemes.

The study was aimed at examining phase equilibria in Na₂O–R₂O₃–B₂O₃ systems (R = In, Sc, Yb). Interactions in these systems were analyzed using the solid-state reaction method. Phase formation in the ternary systems of sodium, rare-earth (scandium, indium, and ytterbium), and boron oxides was studied for the first time in the subsolidus region within the temperature range of 700–750°С. Preliminary triangulation of the analyzed systems was conducted. At 750°С, the isothermal cross sections of Na₂O–R₂O₃–B₂O₃ (R = In, Sc, Yb) systems are represented by eight, thirteen, and eleven triangles of coexisting phases, respectively. The study confirmed the formation of three known double sodium-scandium borates in the Na₂O–Sc₂O₃–B₂O₃ system: Na₃Sc(BO₃)₂, Na₃Sc₂(BO₃)₃, and NaScB₂O₅. Also, a double sodium-scandium borate of approximate composition Na₃ScB₈O₁₅ was found to form, which was indexed as monoclinic (approximate space symmetry group Cc). The unit cell parameters were refined using the Le Bail method: a = 12.625(6); b = 7.725(2); c = 10.409(3), β = 53.19(2)°. The Na₂O–Yb₂O₃–B₂O₃ system contains three new double borates: Na₃Yb(BO₃)₂, Na₃YbB₈O₁₅, and borate with a composition close to the stoichiometric ratio Na₂O•Yb₂O₃•B₂O₃. The formation of the following compounds was first experimentally shown: Na₃YbB₈O₁₅ isostructural to Na₃GdB₈O₁₅ and isoformula Na₃Yb(BO₃)₂, which is not isostructural to Na₃Y(BO₃)₂. The triple oxide system with indium was found to be eutectic, i.e., without the formation of double sodium-indium borates.

Paracetamol (acetaminophen) is widely used around the world as both an analgesic and antipyretic medication. It is effective and safe when taken in therapeutic doses; however, overdosing can result in liver and kidney toxicity in both humans as well as animals. Medicinal plants are important sources of nutrition and healthcare for humans, and many of them have demonstrated protective effects against liver and kidney injuries. This research investigates the liver and kidney protective effects of various Alpinia officinarum (galangal, I) extracts in mice exposed to acetaminophen. Specifically, it examines the effects of extracts obtained using different solvents, including polar and nonpolar organic solvents and aqueous solutions. The study’s findings indicated that essential oil, hydroethanolic, and chloroform extracts have the most significant protective effects on the liver and kidney. These protective effects may attributed to the presence of flavonoids, alkaloids, terpenoids, fatty acids, and phytosterols in these extracts. In conclusion, essential oil, hydroethanol, and chloroform used for the extraction of galangal rhizome effectively isolated various bioactive components, which provided substantial protection against the liver and kidney injuries caused by paracetamol in mice.

This study investigates the biochemical properties of commercial recombinant chymosin samples available on the Russian market. One of the most critical steps in the production of natural cheese is the coagulation of milk into a curd under the action of rennet or other milk-clotting enzymes. While milk coagulation can be induced by various proteases capable of hydrolyzing κ-casein, the quality of the final product significantly depends on the biochemical properties of the enzyme. These properties influence the proteolytic processes occurring in the cheese from production to maturation. In this work, we examined the effects of hydrogen ions, calcium, and temperature on the specific (milk-clotting) activity of the enzyme preparations. The activity was determined in accordance with the industry standard OST 10288-2001 (“Milk-Clotting Enzyme Preparations”). The non-specific (proteolytic) activity was measured using a standard method of E.D. Kaverzneva, adapted for laboratory studies of milk-clotting enzymes. The results demonstrated that the biochemical properties of the tested commercial recombinant chymosin samples were equivalent to those of the industry reference standard for rennet. This finding supports their suitability for producing cheeses with a high second heating temperature, for which the conventional technology uses rennet. In Russia, the production of genetically engineered chymosins is not currently undertaken. Consequently, the development of domestic production technologies for recombinant chymosin remains highly relevant. Such studies are being conducted by the Siberian Research Institute of Cheese Making in collaboration with the State Research Center of Virology and Biotechnology “Vector” (Rospotrebnadzor).

The study was aimed at analyzing the efficiency of thermal esterification of soybean husk polysaccharides with citric acid and its effect on the mechanical characteristics of compressed husks. The thermal treatment of a mixture of husks and citric acid was studied within the temperature range of 110–170 °С without the use of solvents and catalysts. The duration of thermal treatment varied from 30 to 180 min. This process was found to be accompanied by the hydrolysis of husk polysaccharides and their esterification within the analyzed temperature range. The main products of thermal treatment are modified husks and bio-oils. The bio-oils contain predominantly the products of citric acid transformation (55 to 82%). The low-molecular-weight transformation products of husk polysaccharides are represented by furan compounds. The process of esterification was confirmed by the results of studying modified husks via infrared spectroscopy and conductometric titration. The accumulation dynamics of ester linkages in husk biomass were also analyzed in relation to temperature and thermal treatment duration. The cross-linking degree of cellulose polymer chains was found to increase with increasing temperature and thermal treatment duration. Comparative tests of the original compressed husk samples and the modified husks revealed an improvement in their mechanical properties following thermal treatment in the presence of citric acid. A 1.2-fold strength increase and a 2.5-fold stiffness increase were observed. The presented results experimentally confirm the potential of esterification of soybean husks with citric acid, with their use as a filler in the production of composite materials.

Studies on the clarification and compact settling dynamics of apple must provide cider makers with insight into the possibility of using processing aids to achieve must clarification, as well as a better understanding of their usage levels and schemes. The present article analyzes the clarification dynamics of fresh apple must produced from the following cultivars: Margo, Dzhin, Orfey, Karmen, Ekzotika, Liberty, Persikovoe, Amulet, Zolotoe Letnee, and Ketni. In the study, the must clarification was carried out spontaneously (natural settling) and with the use of enzyme preparations, SQzyme PCL and Fructozym P. Must turbidity was determined using a LabScat 2 turbidity meter. The spontaneous clarification of fresh apple must was found to proceed slowly. The use of enzyme preparations significantly enhanced the clarification process. Within 8–16 h of adding SQzyme PCL, a 5–8% decrease was observed in the turbidity of apple must obtained from the cultivars Margo, Dzhin, Orfey, Ekzotika, and Liberty as compared to the spontaneous clarification of must obtained from the same cultivars. The efficacy of Fructozym P. was slightly lower. The compact settling dynamics of must are shown to depend significantly on the varietal characteristics of apple must and clarification duration. The compact settling velocity was calculated. The highest rate was noted in the must obtained from the cultivars Margo, Ekzotika, and Orfey, while the lowest rate was noted in the must produced from the Persikovoe cultivar. The use of SQzyme PCL increased the compact settling velocity by 1.5–4.0 times. The largest increase in the compact settling velocity was observed in the must obtained from Persikovoe and Karmen cultivars.

The Siberian region abounds in fruit and berries, whose potential for use in winemaking is underestimated. The present study aims to assess the suitability of Ussurian pear fruit (Pyrus ussuriensis Maxim.) growing in the South Baikal region for the production of a port-like alcoholic fruit beverage. Ussurian pear fruit has a sweet-sour, astringent flavor and a fairly distinctive aroma with honey and floral notes. An essential characteristic of small-fruited pears in the Siberian region is the significant levels of extractive substances and polyphenolic compounds, which makes them suitable raw materials for the production of fortified dessert vinous beverages. The subject matter of the study was wort obtained from Ussurian pear fruit, having a sugar content of 16.3 g/cm³. Fruit beverages were obtained using an accelerated technology, which included wort conditioning in terms of titratable acidity and sugar levels, wort fermentation, fortification of the fermented fruit material, and thermal treatment of the latter in the presence of oak, apple, and pear chips and pine nut shells. The thermal treatment was performed by heating the fruit material three times to 60 °С for 30 h, followed by cooling to 15 °С. The obtained fortified fruit beverages met the requirements of GOST R 58013-2017 Fruit Wine Drinks. General Specifications in terms of most physicochemical parameters and had a distinctive pear aroma, high transparency, and honey color. The best organoleptic characteristics were achieved in the beverage sample obtained using pine nut shells. Thus, Ussurian pear fruit has high potential as a raw material for producing a port-like fortified fruit beverage.

The present study was aimed at analyzing the ability of a new paraffin-degrading strain, Gordonia amicalis G2, isolated from the contaminated sand of a seaport in Vietnam, to produce biosurfactants. The production of biosurfactants by the Gordonia amicalis G2 strain was monitored during bacterial growth in batch culture with the use of hexadecane as the growth medium. The effectiveness of produced biosurfactants was evaluated in terms of surface and interfacial tension. The surface and interfacial tension of biosurfactant solutions were determined using the du Noüy ring method by means of a Kruss K6 tensiometer. Surface tension decreased to 39 mN/m; interfacial tension, to 2 mN/m. The chemical structure of biosurfactants was characterized using thin-layer chromatography and Fourier transform infrared spectroscopy. A qualitative assessment revealed the glycolipid nature of secondary metabolites. The critical micelle concentration was determined from the inflection point of the curves showing the dependence of surface tension on the biosurfactant content. The critical micelle concentration amounted to 200 mg/L at a constant surface tension of 39 mN/m. The new Gordonia amicalis G2 strain was found to have an effective ability to produce glycolipid biosurfactants. Given the ability of Gordonia amicalis G2 to participate in the synthesis of carotenoids, an integrated technology could be developed for secondary metabolite production by this strain.

The article presents a bioinformatic study of the diversity of CRISPR-Cas systems in the genomes of Clostridium botulinum and the phages they detect, with the aim of their targeted screening. The subject matter of the study was 49 complete chromosomal sequences of bacteria obtained from the GenBank database. Cas genes were identified employing the MacSyFinder tool with the use of HMM profiles from the PFAM and TIGRFAM databases. The identification and analysis of CRISPR cassettes were performed using three independent programs: CRISPRFinder, PILER-CR, and CRISPR Recognition Tool, which ensured high accuracy in determining the cassette structure. Protospacers were identified using the CRISPRTarget tool and the BLASTn algorithm against RefSeq-Viral viral databases. The study involved comparing spacer sequences and phage genomes in order to identify complementary sites. A phage immunity analysis revealed a predominance of Cellulophaga phages (19%), which can be attributed to the environmental characteristics of Clostridium botulinum, as well as a significant proportion of Aeromonas and Bacillus phages (12.5%). Another group of phages (predominantly intestinal) included Enterococcus, Escherichia, and Lactococcus species (6–10%). Also, the protospacers of rare phages (3% each) were found: Acidianus filamentous, Prochlorococcus, Pseudoalteromonas, Stenotrophomonas, and Synechococcus. The obtained results indicate complex CRISPR-Cas systems in Clostridium botulinum, evolving under the impact of different ecological niches.

Melanin, known for its high physiological activity and functional properties, has attracted research interest as a potential antimicrobial agent in food systems and consumer packaging. This study investigated the antimicrobial activity of melanin derived from buckwheat hulls against the bacterial microbiota present in industrially produced cheeses. The research objects were purified melanin obtained from buckwheat hulls and the following microbial strains: Penicillium roqueforti, Bacillus subtilis, Bacillus pumilus, and Lactobacillus plantarum. The disc-diffusion method and the cultivation of test strains in the presence of melanin were employed. Statistical analysis was carried out using Statistica 10 software. The study confirmed the antimicrobial activity of melanin against Gram-positive bacteria Bacillus subtilis B-12587 and Penicillium roqueforti F-1311. At the highest tested concentration, the zone of lysis for Bacillus subtilis B-12587 was 26.4±0.2 mm, which was 1.28 times larger than that of Penicillium roqueforti F-1311 cells, 1.43 times larger than that of Bacillus pumilus B-7308 cells, and 1.58 times larger than that of Lactobacillus plantarum B-3242 cells. A strong correlation (r = 0.97) was identified between melanin concentration in the medium and the growth inhibition of Bacillus subtilis B-12587. These findings highlight the potential of plant-derived melanins as antimicrobial agents in food-grade films intended for primary packaging.

Higher levels of hydrogen peroxide (H₂O₂) in plant tissues improve resistance to a variety of biotic and abiotic stressors. One of the key enzymes involved in the regulation of H₂O₂ levels in plants is peroxidase. The present study was aimed at analyzing the level of endogenous H₂O₂, peroxidase activity, and its isoenzyme spectrum in the roots of in vitro Skarb cultivar and its transgenic lines expressing the Penicillium funiculosum glucose oxidase (gox) gene under normal conditions and with exposure to the phytopathogen Clavibacter michiganensis subsp. sepedonicus. The H₂O₂ level of transgenic lines carrying the modified gox gene was shown to be significantly higher compared to the original cultivar and to increase further due to exposure to the phytopathogen. Under normal growth conditions, differences were observed in the spectrum of peroxidase isoforms in the transgenic lines and the original Skarb cultivar. Upon exposure to the phytopathogen, the spectrum of isoforms was significantly altered in the original Skarb cultivar and in the transgenic lines compared with the Skarb cultivar. The obtained data prove that the product of gox gene expression causes a high H₂O₂ level due to glucose oxidation. High H₂O₂ levels in transgenic lines presumably inactivate peroxidase. Exposure to the phytopathogen Clavibacter michiganensis subsp. sepedonicus is shown to increase peroxidase activity and change the isoenzyme composition in both control and transgenic lines.

The replacement of glucose with glycerol has demonstrated the most significant influence on beta-carotene biosynthesis using Mycolicibacterium neoaurum AC-3067D. However, from a technological standpoint, residual glycerol hinders the drying of biomass, which can be used to produce feed additives for poultry and livestock. This study aims to determine the optimal concentrations of glycerol, glucose, and Tween 80 using a 2³ full factorial experiment, along with testing an optimized medium during the deep cultivation of Mycolicibacterium neoaurum in a 3L bioreactor. We evaluated the accumulation of Mycolicibacterium neoaurum biomass and beta-carotene content in response to the replacement of 20 g/L glycerol with a combination of 10 g/L glycerol and 10 g/L glucose. The results demonstrated comparable productivity of the strain between the modified and control media, yielding 17.8 g/L biomass and 182.5 mg/kg beta-carotene. The study showed that the incorporation of Tween 80 (1 g/L) into the nutrient medium resulted in a 14.0% and 32.2% increase in biomass and beta-carotene yield, respectively, in comparison to the control. The medium, optimized using a 2 3 full factorial experiment, contained glycerol (15.0 g/L), glucose (5.0 g/L), and Tween 80 (1.5 g/L). The cultivation of Mycolicibacterium neoaurum in a bioreactor using this growth medium resulted in a maximum productivity of 376.5 mg/kg of beta-carotene and 25.2 g/L of biomass.

Paving bitumens intended for use in the construction of road, bridge, and airfield pavements do not meet the requirements for crack resistance, heat resistance, elasticity, and adhesion to the surface of mineral materials. Pavement performance can be improved by the addition of thermoplastic elastomers to paving bitumens. These factors determine the relevance of research in this area. This study focused on obtaining polymer bitumen compositions by the addition of styrene/butadiene block copolymers and a plasticizer to paving bitumen, as well as studying some of its properties. Industrial oil I-40 produced by Angarsk Petrochemical Company was used as the plasticizer. BND 100/130 bitumen and styrene/butadiene block copolymers produced in Russia and China were tested. The infrared spectrum of the copolymers exhibits styrene-related absorption bands at 3061, 3024, 1640, 1601, 1450, 1493, 756, 730, and 659 cm^-1; butadiene segments are recorded around 994, 964, and 911 cm^-1. The elemental analysis shows that the content of butadiene segments is 3.1 times higher in the Chinese copolymer than in the copolymer produced in Russia. It was found that with the increasing percentage of copolymer content in the paving bitumens, the dynamic viscosity and extensibility of the composition increase, and its brittleness temperature decreases. With the growing content of butadiene units in the copolymer, dynamic viscosity, softening and brittleness temperatures, penetration, and extensibility increase; for the Chinese copolymer, these parameters are higher than those of the copolymer produced in Russia.

In this work, we investigate the electrochemical and electrokinetic characteristics of electrodeionization extraction of cobalt, copper, and cadmium ions from process solutions of electroplating plants for subsequent recycling. The research objects were selected following a review of publications on the possibility of using electromembrane methods for purification and concentration of industrial wastes. The current–voltage characteristics of the electrodeionization process were studied experimentally. The I–V curves showed the presence of a minimal linear ohmic section at voltages from 1 to 3 V and a plateau with a slight upward slope at the section from 3 to 5 V. Under a further increase in voltage, a region of supercritical current is observed, which is related to the formation of H⁺ and OH^- ions at the membrane–ion-exchange resin interfaces. The kinetic dependencies of the concentrations of retained substances on the residence time in the desalting and concentration chambers of the electrodeionization unit at different current densities and flow rates were analyzed. At a low current density of 5 A/m², three main sections were observed: (1) in the range from 0 to 900 s, where ion accumulation on ion-exchange membranes in desalting and concentration chambers occurs; (2) in the range from 900 to 2700 s, where intensive ion transfer is observed; (3) in the range from 2700 to 3600 s, where electrochemical regeneration of ions in purification chambers takes place. The results obtained were used to develop a technological scheme for wastewater treatment from heavy metal ions.

Lactic acid and its salts (lactates) are used extensively in the food industry as acidity regulators and as raw materials for the synthesis of polylactide, a biodegradable packaging material. Currently, the prevailing method of producing lactic acid involves the biosynthetic pathway, using sugar-containing raw materials such as beet molasses. This study aims to examine the process of molasses bioconversion into lactic acid using the anaerobic strain Lactobacillus acidophilus AT-I. The concentrations of carbon (molasses) and nitrogen (yeast extract) were optimized using a central composite design experiment. The lactic acid content in the culture liquid was analyzed using capillary electrophoresis. The model was constructed in the R environment, and its adequacy was assessed using Fisher’s F-test. The findings demonstrated that the model adequately described the experimental data at a significance level of 0.05 (the variance of adequacy of the regression equation of 0.28, R² = 0.76, the calculated value of the F-criterion (3.2) is less than the tabulated value (6.3)). According to the model, the highest conversion of molasses to lactate (5.6%) should be observed at a molasses concentration of 63 g/L and a yeast extract concentration of 1.9 g/L. The cultivation of Lactobacillus acidophilus AT-I in a bioreactor exhibited classical kinetics of carbohydrate breakdown and lactic acid accumulation, with lactic acid content reaching 5.5 g/L after 96 hours.