The study aims to assess how the structure of carbocations, including solvated carbocations – derivatives of ethylene glycol vinyl glycidyl ether (Vinylox) – affects their enthalpy of formation, geometry, and frontier orbital energies via a semiempirical quantum chemical method (Parametric Method 3). In this work, the enthalpy of Vinylox formation was calculated, as well as the energies of frontier (highest occupied and lowest unoccupied) molecular orbitals of carbocations formed during the heterolytic cleavage of vinyl oxide and epoxy groups. The calculations were performed with full geometry optimization. The characteristics of nine model structures (the subject matter of the study) that could potentially participate in cationic macromolecular chain growth processes were determined. It was found how the intramolecular and intermolecular anomeric (“through space”) effects, involving the interaction of simple ether and epoxy oxygens with carbocation centers, affect the enthalpy of formation and frontier orbital energies. In all cases, the spatial geometry of structures with intramolecular anomeric interactions is bent. The geometry of the epoxy carbocation is linear due to the absence of such interactions. These interactions were found to significantly reduce both the enthalpy of carbocation formation and the energy of the highest occupied molecular orbitals. It is possible that such anomeric interactions are of donor-acceptor type, involving the unshared electron pairs of oxygen and the vacant p orbitals of carbocation centers. It is assumed that these interactions also occur in weakly polar aprotic solvents (chlorohydrocarbons), as proven by the example of chloroform.

The study aims to provide an analytical review of synthetic components, such as polyethylene glycol and acrylic acid, used in the production of hydrogels, identify their advantages and disadvantages, and explore the potential applications of these materials in tissue engineering. Hydrogels constitute cross-linked three-dimensional polymers that, due to the presence of hydrophilic particles, are capable of absorbing large amounts of liquid. The physicochemical properties of hydrogels are adjusted depending on the task and are determined by the composition, component concentration, cross-linking methods and density, manufacturing methods, and the presence of additives. Hydrogels are used in various fields, including biomedicine, biotechnology, and bioengineering. It is known that components for the manufacture of hydrogels can be divided into natural, synthetic, and semi-synthetic. Unlike hydrogels prepared from natural components, synthetic hydrogels have the advantage of high reproducibility. Synthetic hydrogels offer greater flexibility in terms of chemical composition and mechanical properties, which can be adapted for specific applications by incorporating functional groups, and their transport properties can be modified by adjusting the length and density of polymer chains. Synthetic polymers have now become an important alternative in the preparation of hydrogel scaffolds, as they can be molecularly adjusted, taking into account the structure, molecular weight, mechanical strength, and biodegradability. The present article provides basic information about hydrogels, describes their structure and classification, and discusses the main synthetic components for hydrogel compositions and ways to use them.

This study investigates the sorption kinetics of phosphates onto a calcined sorbent derived from ash and slag waste generated by thermal power enterprises. The performance of the sorbent was also tested on water from an open discharge into the Kuban River, which contained a mixture of stormwater and domestic wastewater. The sorbent was prepared by drying and calcining ash and slag samples from the Novocherkassk State District Power Plant at 600 °C for 30 minutes. This paper details experiments on the static sorption removal of phosphates from both model aqueous solutions and wastewater. In the kinetic studies using model solutions, a sorbent dose of 1 g per 50 cm³ of solution was used. The optimal sorption parameters were determined experimentally: an agitation speed of 200 rpm, a pH of 7, and a contact time ranging from 10 to 120 minutes, with initial phosphate concentrations ranging from 2 to 300 mg/L. A high removal efficiency of 97–98% was achieved at initial concentrations of 10 and 20 mg/L. The experimental data were analyzed using pseudo-first-order (Lagergren) and pseudo-second-order (Ho – McKay) kinetic models. The pseudo-second-order model provided the best fit, with a coefficient of determination R² of 0.999, which is consistent with literature on phosphate sorption from aqueous solutions. A strong agreement was observed between the experimental and calculated values for phosphate removal efficiency.

The protonated form, 2-chloropyridinium chloride, was synthesized and characterized spectroscopically for the first time to eliminate the influence of the basic nitrogen center in pyridine on the stability of the resulting isothiuronium salt. This compound readily condensed with thiourea to form the corresponding isothiuronium salt. Nuclear magnetic resonance (NMR) spectroscopy (¹H and ¹³C) revealed that the salt exists as two stable conformers differing in the orientation around the C2–SC(NH₂)₂ bond. These conformers are most clearly distinguished in the ¹³C NMR spectra by the chemical shift of the C4 signal in the pyridine ring relative to its position in neutral 2-chloropyridine. The presence of two stable conformers, determined by an additional basic center in the α-position, may represent a general pattern for this class of compounds. The synthesized pyridinium isothiuronium chloride was investigated as a brightener in a nickel plating electrolyte. Preliminary tests using a Hull cell identified an effective concentration range of 0.10–0.45 g/L and operational current densities of 3–20 A/dm². The addition of the agent at 0.40–0.45 g/L to a sulfate nickel plating electrolyte produced bright nickel coatings with high current efficiency, low porosity, and increased hardness. The microhardness of the coating was found to increase with the additive concentration.

The study aims to develop a bioassay procedure for assessing goat milk quality under production conditions using Escherichia coli M-180 bacteria. The main test reactions of the biomodel yielded resistance to 10 mM hydrogen peroxide and growth characteristics (specific growth rate and biomass accumulation). The proposed method for assessing milk quality is intended for milk samples heat-treated under industrial pasteurization conditions, which ensure the destruction of Escherichia coli in native dairy raw materials. The study examined samples of goat milk heat-treated under the following pasteurization conditions: at 65°C for 30 minutes; at 76°C for 5 minutes; at 90°C for 20 seconds; at 95°C for 5 minutes. A series of experimental studies established the possibility and prospects of using the bioassay procedure with Escherichia coli M-180 as the test object (introduced into the culture medium at a volume concentration of 0.125×10⁻³ mL/mL) to assess the quality of casein dairy raw materials under production conditions. The selected bioassay was shown to be highly sensitive, which is confirmed by the growth characteristics (growth rate and biomass accumulation), as well as data on the hydrogen peroxide resistance of Escherichia coli M-180. It was found that the industrial pasteurization conditions of 76°C for five minutes and 90°C for twenty seconds are the most effective, ensuring the highest preservation of native biologically active substances in goat milk.

Recent decades have seen increased interest in black truffles due to their gastronomic properties, high nutritional value, and potential medicinal properties. An important contribution to the specific aroma and nutritional value of these fungi is made by the community of microorganisms that inhabit truffle fruiting bodies. The present study aims to isolate pure cultures of cultivated fungal symbionts, assess their mutual antagonism, and consider their ecological role. The experiment involved collecting the fruiting bodies of the black truffle, which were used to isolate pure cultures of fungal symbionts. As a result, eight fungal strains were identified. The antagonistic properties of the obtained strains were evaluated using the agar-well method. Six of the eight strains exhibited antagonistic activity. The highest activity was exhibited by the Fusarium sp. strain LPB2023712, which inhibited the growth of six other strains with the maximum inhibition zone of ±3.3 cm. Also, significant activity was observed in the strains of Trichothecium sp. and Hypopichia sp., which inhibited the growth of Clonostachys sp. and Penicillium sp. The obtained results indicate the important role of fungal symbionts in the ecology of truffles, including their ability to regulate the microbial community and inhibit the development of pathogens in fruiting bodies. The Fusarium sp. strain LPB2023712 demonstrated potential to serve as a biocontrol agent, which opens up new opportunities to find biologically active compounds and develop methods for improving the resistance of truffles to disease. This study emphasizes the need for further research on truffles and associated microorganisms to gain a deeper understanding of their ecological functions, interactions, and practical applications in agriculture and biotechnology.

The modification of nonwoven fabrics designed to impart antibacterial properties is an important process in the manufacture of a wide range of medical products, including medical face masks, wound dressings, surgical drapes, etc. However, apart from antibacterial properties, the effect of modification on the consumer properties of nonwoven fabric is also of interest. The present study was aimed at examining the consumer and antibacterial properties of nonwoven fabric modified with chitosan. In addition to exhibiting antibacterial activity, chitosan is also a biocompatible hydrophilic polymer. In this study, four industrial grades of chitosan were examined: Premium Quality chitosan (Italy), food-grade acid-soluble chitosan, chitosan succinate, and low-molecular-weight food-grade water-soluble chitosan (Russia). It was found that of the studied chitosan grades, food-grade acid-soluble chitosan and Premium Quality chitosan exhibit antibacterial activity. The treatment of hydrophilic nonwoven fabric obtained using the spunbond technology with a chitosan solution leads to a decrease in air permeability by 19% and an increase in stiffness by 77%. When chitosan solution concentrations of up to 0.2% are used, vapor permeability increases; however, a further concentration increase leads to a decrease in this parameter. Within the analyzed range, the hygroscopicity does not change. The study results indicate the inexpediency of impregnating medical nonwoven fabrics with chitosan solution at concentrations higher than 0.2%, since at higher concentrations, the consumer properties (air and vapor permeability) of modified nonwoven fabric deteriorate.

The enzymatic hydrolysis of pretreated lignocellulosic feedstock is a critical step in the production of value-added biosynthesis products. This work presents a comparative evaluation of commercial enzyme preparations and their combinations for converting oat hulls following nitric acid pretreatment. Hydrolysis was carried out at an initial substrate concentration of 30 g/L, pH 4.7, and a temperature of (46±2) °C. The study evaluated three enzyme preparations from different manufacturers, including Agrocell Plus (Agroferment LLC, Russia), Cellolux-A (Sibbiofarm LLC, Russia), and Ultraflo Max (Novozymes A/S, Denmark). The evaluation of the individual preparations revealed that the yield of reducing substances from the substrate mass was 53%, 40%, and 51%, respectively. The addition of supplementary β-glucanase (Ultraflo Max) to the enzyme preparations Agrocell Plus or Cellolux-A, which exhibit high cellulase activity, resulted in a 1.3–1.5-fold increase in reducing substance yield. The maximum yield of reducing substances of 72%, corresponding to 99% hydrolysis of the available substrate portion, was observed during hydrolysis using a combination of all three enzyme preparations. Scanning electron microscopy of the substrate before and after hydrolysis confirmed the effectiveness of the mixed preparations and revealed a difference in the residual fragmented substrate after hydrolysis by the individual preparations versus the multi-enzyme compositions, in favor of the latter. All hydrolysates obtained from the nitric acid-pretreated oat hulls were characterized as glucose-based, with the total concentration of glucose amounting to 85–91%. This composition suggests a high potential for successful use in subsequent biosynthesis processes.

This study examines the biochemical composition of an aqueous extract from the spent mushroom substrate of oyster mushroom (Pleurotus ostreatus strain HK-35) and investigates its regulatory and protective properties. The major organomineral components of the extract included approximately 2% dry matter, comprising over 1.5% organic matter and less than 0.5% ash. The extract had a mildly alkaline pH. Primary organic components included proteins, carbohydrates (predominantly reducing sugars), and humic substances, with potassium, calcium, and phosphorus being the most abundant elements. In germination assays, a 10% extract enhanced wheat seed germination, whereas a 100% extract inhibited it. The 10% extract also enhanced superoxide dismutase activity and the expression of the SOD-1 gene and suppressed peroxidase activity. This treatment had no effect on catalase activity or the transcript levels of the studied CAT and POD genes. In contrast, the 100% extract suppressed peroxidase activity and gene expression; however, it had no effect on superoxide dismutase or catalase activity or their related gene transcripts. In antifungal assays, the 10% extract significantly inhibited the growth of phytopathogens in vitro. The mycelial mass of Aspergillus niger was reduced by more than 6-fold and its colony radius by almost 8-fold, while for Alternaria alternata, mass was reduced by more than 7-fold and colony radius by approximately 15-fold, compared to the control.

The annual generation of wood waste in the Russian Federation is currently estimated at 75–113 million cubic meters. The conversion of these lignocellulosic residues into value-added products, including bioenergy sources, feed additives, and organic acids, constitutes a priority within the nation’s environmental policy framework. This study details the production of a protein-rich product from the biomass of the non-conventional yeast Meyerozyma guilliermondii strain Y-780 cultivated on a hydrolysate derived from sawmill waste. An analysis of the cultivation process revealed that the yeast metabolized the bulk of reducing substances within the first 48 hours, concomitant with a phase of vigorous biomass accumulation. The investigation of the pH influence revealed that the strain Y-780 of Meyerozyma guilliermondii exhibited substantial yeast growth on the hydrolysate at a pH of 4.6. The incorporation of corn extract into the mineral culture medium based on the hydrolysate led to an almost threefold increase in biomass yield compared to media containing only inorganic nitrogen sources. The research established a distinct consumption profile for reducing substances by the yeast, which was highly dependent on the composition of the culture medium. The addition of nitrogen, vitamins, and biogenic elements to the hydrolysate resulted in an enhancement of its nutritional value, leading to an increase in crude protein yield to 47%. These findings suggest the biological suitability of the wood sawdust hydrolysate and underscore the significant biotechnological potential of Meyerozyma guilliermondii strain Y-780 for feed protein biosynthesis.

This study examines a method for decaffeinating mate tea, an infusion made from Ilex paraguariensis leaves. A popular beverage in South America, mate is now available on the Russian market. Reversed-phase high-performance liquid chromatography on a Kromasil 100-5C4 phase was used to analyze the major components of the infusion. The conventional C18 phase was replaced to prevent modification by β-cyclodextrin, as chlorogenic acids in the infusion form host–guest complexes with it, thereby reducing caffeine adsorption on bentonite clay. The targeted adjustment of key mobile phase modifiers controlled the elution position of caffeine relative to monocaffeoylquinic acids. A gradient elution mode enabled the simultaneous detection of caffeine, mono-, and dicaffeoylquinic acids. The use of Na⁺-form bentonite clay removed over 95% of the caffeine. However, this process incurred substantial losses of approximately 25% of monocaffeoylquinic and 50% of dicaffeoylquinic acids. Since dicaffeoylquinic acids form more stable inclusion complexes with β-cyclodextrin than their monocaffeoyl counterparts, the addition of β-cyclodextrin to the beverage was proposed. Both bentonite clay (an effective enterosorbent) and β-cyclodextrin are approved for food and pharmaceutical use. This approach reduced the losses of both mono- and dicaffeoylquinic acids by more than half.

The metabolites of the basidiomycete Daedaleopsis tricolor have attracted research attention due to their antioxidant, antimicrobial, and antitumor properties. This study investigated the submerged cultivation of the Daedaleopsis tricolor strain KS11 in nutrient media supplemented with varying nitrogen sources, including yeast extract, soy protein isolate, and a 1:1 combination thereof. The cultivation on the combined medium yielded up to 9 g/L of biomass and reduced the cultivation time by one day compared to media containing a single nitrogen source. The total pool of exometabolites obtained using the combined medium demonstrated high antioxidant (88.61 mg/g) and antiradical activity (3.41 mg/mL). This activity correlated with a high flavonoid content of 18.56 mg/g, which exceeded the levels found in exometabolites from the other media. The use of soy protein isolate as a nitrogen source was more effective for the synthesis of endopigments. These endopigments were identified as melanins by infrared spectrometry. The cultivation of Daedaleopsis tricolor KS11 on a combined medium containing a 1:1 ratio of yeast extract and soy protein isolate represents a promising approach, as it facilitates the concurrent accumulation of exopigments and endopigments with high antioxidant properties. These findings provide a basis for developing dietary supplements with enhanced antioxidant activity.

This study aimed to synthesize a pour-point depressant for diesel fuel using intermediate products and waste materials from the Angarsk Petrochemical Company and the Angarsk Polymer Plant (Angarsk, Russia). The work provides a brief review of the quality requirements for diesel fuel and demonstrates the quality of base diesel fuels produced by Angarsk Petrochemical Company. The study characterizes the depressant-dispersant additives used in the production of commercial diesel fuels, along with the research methods and objects. The mechanism of interaction between styrene and low-molecular-weight polyethylene during radical copolymerization was established. The key patterns of the styrene and low-molecular-weight polyethylene copolymerization process were identified, and the structure of the resulting copolymer was determined. The depressor effect of the additives was assessed in base diesel fuels with different low-temperature characteristics. The relationship between the low-temperature characteristics of the base diesel fuels and the additive concentration was illustrated. The use of the novel pour-point depressants at concentrations of 0.1–1.0 wt% was found to reduce the pour point to -42 °C, thereby achieving a depression of the cold filter plugging point to 21 °C. The use of the developed pour-point depressant facilitates the production of value-added interseasonal diesel grades D and E from summer diesel grade A base fuels without altering the fractional composition. In addition, the value-added winter diesel classes 0, 1, and 2 can be obtained from winter diesel grade D base fuels.

The present study aims to evaluate the efficiency of culturing yeast strains and yeast-like fungi in media derived from the byproducts of the brewing process, such as brewer’s spent grain and its enzymatic hydrolysate. The study used the following feed protein producers: Saccharomyces cerevisiae strains (Y-365, Y-722, and Y-1155) and a strain of yeast-like fungi, Saccharomycopsis fibuligera strain Y-310, from the All-Russian Collection of Industrial Microorganisms. Changes in the number of these microorganisms were studied in the process of their culturing in brewer’s spent grain without the use of a multienzyme composition and in its enzymatic hydrolysate. Bioconversion efficiency for reducing sugars and changes in protein concentration during culturing were determined. It was shown that in order to increase the efficiency of bioconversion of brewer’s spent grain, a pre-treatment of raw materials using a complex of cellulolytic, hemicellulase, and proteolytic enzymes is recommended; the products of enzymolysis are monosaccharides, disaccharides, and amino acids, which are the sources of energy, carbon and nitrogen, necessary for further production of microbial protein. The bioconversion of reducing sugars was experimentally confirmed to have the maximum efficiency of 78.6%; also, a 10.5-fold increase in the amount of protein was observed when culturing Saccharomyces cerevisiae strain Y-365 in the enzyme lysate of brewer’s spent grain. The study results can be used in obtaining feed additives through the biofermentation of brewer’s spent grain with Saccharomyces cerevisiae strain Y-365 and will enable a better use of brewer’s spent grain, increasing its nutritional value and digestibility.