Vol 14, No 3 (2024)
Chemical Sciences
Gluconate solutions for nickel electrodeposition and nickel electroless plating
Abstract
Nickel electroplating has found a wide range of industrial applications as a technique for creating protective and decorative coatings of metallic and non-metallic surfaces, protecting materials against corrosion at elevated temperatures in both alkaline environments and organic acid solutions, forming a sublayer for obtaining coatings of other metals on steel, enhancing the hardness and wear resistance of surfaces, as well as for improving solderability. Such coatings can be obtained from weakly acidic aqueous and weakly alkaline complex electrolytes. In this review, we analyze the available literature on complexation of nickel(+2) with D-gluconate ion CH2OH(CHOH)4COO‾, along with that on compositions and some technological characteristics of complex D-gluconate solutions for nickel electrodeposition and electroless plating. Thus, a corrosion-resistant smooth light-colored nickel coating, tightly adhered to a copper substrate, was obtained from an electrolyte with a pH level of 8, containing 53 g/dm3 of NiSO4 •6H2O, 44 g/dm3 of D-C6H11O7Na, 25 g/dm3 of H3BO3, 53 g/dm3 of (NH4)2SO4, and 0.5–3 g/dm3 of CO(NH2)2, at a temperature of 25 °C, a cathodic current density of 2.5 A/dm2 with a current efficiency of 96.4%. An electroless Ni-P(3–18 wt%) alloy coating on copper was obtained from a solution with a pH level of 9, containing 5–30 g/dm3 of NiSO4 •6H2O, 10–60 g/dm3 of D-C6H11O7Na, 5–40 g/dm3 of NaH2PO2 •H2O, 3 g/dm3 of HOOCCH2CH2COOH, 0.5 g/dm3 of CH3(CH2)11OSO3Na, 0.002 g/dm3 of Pb(CH3COO)2•3H2O, at a temperature of 90 °C and a deposition rate of up to 0.75 μm/min. The review also discusses methods for preparing D-gluconate electrolytes for nickel plating using sodium D-gluconate, D-glucono-1,5-lactone, and nickel D-gluconate. One advantage of D-gluconate nickel plating solutions consists in the absence of toxicity and low cost of D-gluconates.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):298-304
298-304
Synthesis of grafted copolymers of cod collagen and acrylamides in the presence of alkylborane – p-quinone system
Abstract
The graft polymerization of acrylamide and N-isopropylacrylamide onto collagen in the presence of triethylborohexamethylenediamine complex and a number of p-quinones, including benzoquinone, naphthoquinone, 2,5-di-tretbutyl-p-benzoquinone, and duroquinone, was studied. In all cases, p-quinones act as polymerization retarders, reducing monomer conversion. An exception is the graft polymerization of acrylamide onto collagen in the presence of benzoquinone, which acts as a polymerization inhibitor. The proportion of the synthetic fragment in the obtained copolymers is determined by the structure of the monomer and p-quinone. The molecular weight distribution curves contain modes related to unreacted collagen, which differ significantly from those of the initial collagen in terms of intensity. This is related to the formation of a grafted copolymer of cross-linked structure, which cannot be analyzed by gel permeation chromatography. The degradation of copolymers under the action of enzymes was controlled by gel permeation chromatography. Enzymatic hydrolysis of copolymers proceeds slower than that of collagen, which confirms the formation of a copolymer. Following three hours after the onset of hydrolysis, the molecular weight distribution curves contain low-molecular weight modes of collagen and low-intensity modes related to polyacrylamide. The morphology of copolymers differs from that of collagen and polyacrylamides. Cytotoxicity evaluation of copolymers is an important research stage, determining their prospects as the basis of materials for regenerative medicine. An analysis of extracts obtained from the copolymers using culture medium by MTT assay showed a high rank of their toxicity, which can be reduced by dilution of collagen and N-isopropylacrylamide copolymer extracts with aqueous solutions. For the copolymers of collagen and acrylamide, the toxicity is maintained due to the high toxicity of the monomer. Their toxicity can be reduced by extraction of unreacted acrylamide with chloroform.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):305-321
305-321
Dielectric parameters of polymers and monomers of the vinyl series in the microwave range
Abstract
The production of polymeric materials is one of the fast-growing sectors in the chemical industry. Improving methods for synthesizing high-molecular compounds and studying their physicochemical characteristics are important tasks of synthetic chemistry. Radical polymerization is currently the main method for producing polymeric materials. Its advantages involve simplicity and low cost, along with the possibility of obtaining a wide range of polymeric materials. The results of measuring the dielectric parameters of various high-molecular compounds (polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, poly(glycidyl methacrylate)) in the frequency range of 100–200 GHz (refractive index and dielectric loss tangent tgδ) are presented. The compounds under study were both those synthesized by radical polymerization with the participation of the conventional initiator, i.e., azobisisobutyric acid dinitrile, and commercial products. The absorption capacity of polymers at room temperature was compared. Polymers with the highest and lowest absorption capacity were determined. The dependence of tgδ on frequency for all the polymers under study is linear, with absorption in the polymers increasing with frequency. Poly(glycidyl methacrylate) exhibits the highest absorption among the studied macromolecules with tgδ being equal to 0.043 at 200 GHz. The minimum tgδ value of 0.0068 was found for polystyrene. For the polymers under study, the refractive index value varies in the range from 1.09 to 1.39. In addition, dielectric properties of the original vinyl monomers (styrene, vinyl acetate, glycidyl methacrylate) were studied. The results are of interest when developing approaches to obtaining polymeric materials with specified characteristics based on vinyl monomers by the method of radical polymerization.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):322-329
322-329
Synthesis, structure, and biological activity of sodium, zinc, and magnesium mono- and bis-1-alkoxy-4-(2′-naphthyl)-1,4-dioxo-2-buten-2-olates
Abstract
The search for new biologically active compounds is a key area of chemical science. Therefore, the synthesis of compounds with a potentially bactericidal effect seems relevant. In order to extend the range of biologically active substances, the synthesis of sodium 4-(2’-naphthyl)-1,4-dioxo-1-ethoxy-2-buten-2-olate and sodium 1-butoxy-4-(2´-naphthyl)-1,4-dioxo-2-buten-2-olate was carried out by Claisen condensation of equimolar amounts of 2-acetonaphtone and dialkyloxalates in a non-polar medium in the presence of sodium as a condensing agent. Bidentate mononuclear metal chelates were obtained by the metal exchange reaction of sodium oxoenolates with Zn(II) and Mg(II) salts. The structure of the synthesized compounds was confirmed by infrared spectroscopy, (1Н, 13С) nuclear magnetic resonance spectroscopy, and mass spectrometry. The infrared spectra of solid samples of sodium oxoenolates and metal complexes contain bands of stretching vibrations of ester carbonyl groups, skeletal vibrations of aromatic rings, as well as “ether” bands due to vibrations of C–O–C bonds. The 1Н and 13С nuclear magnetic resonance spectra recorded in CDCl3 and Dimethyl sulfoxide-d6 are characterized by a complete set of all expected signals with chemical shift values that are well comparable with the reference data. In the mass spectra of the analyzed compounds, recorded in an acetonitrile solution in the electrospray mode, signals of [M+H]+ and [M+Na]+ protonated and cationized molecules are observed. The bactericidal action of the synthesized preparations was assessed using the agar well diffusion method in combination with the serial dilution method. The biological activity of sodium 4-(2’-naphthyl)-1,4-dioxo-1-ethoxy-2-buten-2-olate against Pseudomonas Aeruginosa and Staphylococcus Aureus, as well as sodium 1-butoxy-4-(2’-naphthyl)-1,4-dioxo-2-buten-2-olate against Pseudomonas Aeruginosa, was revealed. Pronounced resistance of Salmonella spp. to the studied compounds was established.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):330-338
330-338
Physico-chemical biology
Nanostructured materials as hazardous wastewater micropullutants: Sources, behavior, and impact on functional bacterial community of activated sludge
Abstract
Unique properties of nanoscale materials make them attractive for industrial, medical, agricultural, and environmental applications. Nevertheless, the release of nanoparticles into the environment is a major concern due to the lack of knowledge about their behavior in the environment and potential widespread environmental impacts. On the one hand, nanomaterials are perceived as pollutants that may affect activated sludge microorganisms and, consequently, the efficiency of wastewater treatment processes. On the other hand, some nanomaterials can be intentionally added to activated sludge systems to improve their performance in terms of, e.g., sludge settling and removing heavy metals or organic pollutants. As a result, nanoparticles are frequently accumulated in wastewater, which is considered to be a major source of nanoparticle release to the surrounding environment. Processes that involve the action of activated sludge are used worldwide in wastewater treatment plants due to their excellent capacity of removing nutrients, degrading toxins, and retaining biomass. High concentrations of nanoparticles entering activated sludge systems can affect their growth and metabolism. The research studies, which are reviewed in the present article, show that nanoparticles significantly reduce the relative abundance of the activated sludge microbial community associated with nitrification, denitrification, and phosphorus removal. The knowledge about the structure of the activated sludge microbial community with an assessment of nanomaterial toxicity can contribute to optimizing the sludge population and improving the performance of wastewater treatment plants.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):339-351
339-351
Influence of physicochemical factors on the specific activity of proteases used in cheesemaking biotechnology
Abstract
The formation of a clot under the influence of proteolytic enzymes is an essential stage in cheesemaking technology. Depending on their composition, milk-clotting enzyme preparations have a different effect on the quality characteristics of the clot, whey separation, and yield of the finished product. At present, the Russian market offers a wide range of domestic and imported milk-clotting enzyme preparations. In this connection, the choice of a milk coagulant by cheese makers should be carried out in accordance with the cheese group produced by the enterprise. The milk-clotting activity of enzyme preparations depends not only on the active acidity of the mixture, but also on the temperature of the solution used to obtain them. It is the solution temperature that has a determining effect on the duration of the coagulation process and, therefore, the quality of the formed clot. Research into the specific activity of milk-clotting enzyme preparations, obtained in a working solution with different active acidity (pH from 4.0 to 8.0), showed their milk-clotting activity to decrease significantly upon pH shifting to the alkaline region. Application of solutions with a pH of 4.0 led to an increase in the milk-clotting activity of bovine pepsin, VNIIMS SG-50 rennet-bovine preparation, and rennet enzyme by 94, 72, and 36%, respectively, relative to the control. Bovine pepsin demonstrated the highest sensitivity to fluctuations in active acidity. A study into the effect of substrate temperature in the range from 30 to 40 °C established rennet to be the most sensitive preparation to temperature changes. It is concluded that a properly selected enzyme composition is an effective means for affecting the quality of cheese products.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):352-361
352-361
Storage stability of phycobiliproteins in a hydroalcoholic solution evaluated by an optical method
Abstract
The aim was to evaluate the stability of pigments of the phycobiliprotein group extracted from the biomass of the Spirulina (Arthrospira) platensis cyanobacterium and the Porphyridium purpureum red microalgae. Water extracts of phycobiliproteins were obtained following a double freezing of the raw biomass of Arthrospira platensis and Porphyridium purpureum. An extraction was carried out with a phosphate buffer (0.05 M, pH = 7) in the cold (5 °C) for 24 hours. To the extracts obtained, 96% ethanol was added until its concentration in the solution was 20%. The hydroalcoholic extracts of phycobiliproteins were stored for three months. Pigment concentrations were monitored by an optical method. The allophycocyanin pigment demonstrated the highest storage stability. The highest degradation rate of phycobiliproteins was observed during their storage in the light at room temperature. The degradation rate of pigments under these conditions was 9and 80-fold higher (for B-phycoerythrin and C-phycocyanin, respectively) than similar indices during their storage in the dark and in the cold. C-phycocyanin was the least stable, compared to other studied phycobiliproteins. Its degradation rate under all storage options was 5to 10-fold higher than that of B-phycoerythrin under similar conditions. An essential conservation requirement for C-phycocyanin and β-phycoerythrin in hydroalcoholic solutions was the absence of light. For C-phycocyanin, a low temperature was necessary as well. Storage of B-phycoerythrin in the dark at room temperature is acceptable. These conditions can ensure the conservation of up to 86% of pigments in hydroalcoholic solutions for 25–30 days.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):362-370
362-370
Technological aspects of birch bark processing into a component of food systems for the population of the Arctic and the Far North
Abstract
Betulin-containing micronutrients increase the quality, physiological activity, and shelf life of food systems. Such micronutrients are relevant for developing physiologically functional food products for the population residing in the regions of the Arctic and the Far North. In this research, we aim to optimize the process of extracting betulin from Betula pendula Roth. For use in food systems for nutritional support of the population residing in regions with extreme climatic conditions by the method of mathematical modeling. Birch bark was harvested in the summer months of 2015–2021 in the foothill zone of the Altai Krai. Mathematical optimization of the process of betulin extraction from birch bark of white-trunked birches (Betula pendula Roth.), containing more than 20 wt% of the main substance, under autoclaving conditions was carried out using the Statistica 10 software package. Based on an analysis of response surfaces constructed using a regression equation, optimal parameters for betulin extraction with ethyl alcohol were determined. Thus, the birch bark particle size equals 3×3 mm; hydromodulus is 1:5; process duration is 150 min. Under these parameters, the betulin yield achieved more than 97%, with its authenticity and safety being confirmed experimentally. The physiological activity of betulin, as well as its usage examples in various food systems to prolong shelf life, prove its feasibility as a natural preserving agent. In addition, betulin can be used as a functional component, i.e., as an antioxidant for enriching food products, in particular, those intended for the population residing in extreme climatic conditions of the Arctic and the Far North.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):371-382
371-382
Dried Laminaria thalli extract for stimulating germination and digestibility of oats and buckwheat
Abstract
Despite their beneficial properties, cereal crops contain a number of antinutritive substances, the amount of which can be reduced by germination. In this work, we test the hypothesis about the possibility of stimulating the germination of cereal crops (on the example of oats and buckwheat) and increasing their digestibility using a dried Laminaria thalli extract. The research was conducted using hulless oats (Avena nudisativa) for germination and hulled buckwheat grain (Fagopyrum esculentum), as well as dried Laminaria thalli. Germination was carried out at a temperature of (20±2) °C for 120 h, using drinking water (control) and drinking water with addition of 1 wt% of dried kelp thalli. The germination intensity was assessed based on the mass of 1000 grains, sprout length, and the number of germinated grains. In all samples, the mass fraction of extractive substances and dry matter digestibility with modifications were determined. It was found that the addition of dried Laminaria thalli to water in the amount of 1 wt% stimulates the germination of oats and buckwheat, as well as their digestibility, significantly. The experimental samples demonstrated an improved water absorption and an increase in the weight of 1000 grains, sprout length, and the number of germinated grains. The use of dried Laminaria thalli extract in germination of oats and buckwheat for food purposes reduces the technological process up to two days with a simultaneous increase in digestibility and minimization of losses of extractive substances.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):383-393
383-393
Enzymatic hydrolysis of highly concentrated substrates obtained from Miscanthus giganteus
Abstract
This work is the first to study the enzymatic hydrolysis of four types of substrates obtained from Miscanthus giganteus of the KAMIS variety of Russian breeding. The study was conducting using the authors’ methodology based on a chemical pretreatment of substrates at atmospheric pressure with HNO3 and NaOH dilute solutions. A one-stage pretreatment of Miscanthus giganteus allows the polysaccharide content to be increased up to 90.4–90.8%, compared to 98.3–99.4% following a two-stage treatment. The experimental results of enzymatic hydrolysis of the four obtained substrates in the range of initial concentrations from 30 to 120 g/l are approximated using fractal kinetics approaches. An increase in the initial substrate concentrations in the specified range leads to an increase in the initial hydrolysis rate by 2.8–3.3 times and a decrease in the yield of reducing sugars by 12.4–13.1%. All four pretreatment types turned out to be extremely effective for Miscanthus giganteus, ensuring an increase in the reactivity to enzymatic hydrolysis by 34–36 times compared to the starting raw material. Lowered yields of reducing sugars are observed during enzymatic hydrolysis of the alkaline delignification product of Miscanthus giganteus, which is associated with the resistance of Miscanthus giganteus to treatment with sodium hydroxide. An increase in the initial concentration of substrates from 60 to 90 g/l does not lead to a significant decrease in the yield of reducing sugars. Therefore, enzymatic hydrolysis of highly concentrated substrates can be successfully used to produce biofuels and biochemicals.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):394-405
394-405
Biochemical composition of biological substances extracted from red deer antlers
Abstract
We aim to study biologically active agents in biological substances obtained from different parts of red deer antlers. Frozen red deer antlers were separated into skin and antler base, crushed, and subjected to ultrasonic enzymatic hydrolysis. The press cake from the extraction of antler base was dried in a vacuum unit. The content of protein, fat, ash, and moisture in the obtained biological substances was studied. In addition, the amino acid, fatty acid, and mineral compositions were analyzed, as well as the molecular weight distribution of peptide fractions. The concentrates from the skin and base of red deer antlers were found to contain the maximum of proteins (73.68–74.41%). The mineral biological substances comprise the maximum of macroand microelements (84.17%), in particular, a high level of 136,000 mg /kg of phosphorus, 29,230 mg /kg of sodium, and 5,140 mg /kg of calcium. All biological substances are characterized by a low-fat content in the range from 0.3 to 1.76%. Similar to the protein content, the total amount of amino acids prevails in concentrates from the skin and base of red deer antlers, equaling 40.90 and 43.66 g /100 g, respectively. Moreover, in both samples, the amount of essential amino acids is higher than that of non-essential ones. The amount of vitamins is low, being represented by B1, B2, B6 water-soluble vitamins. The fatty acid composition is most balanced in the concentrate from the red deer antler base, containing omega-3 and omega-6. The ratio of unsaturated to saturated fatty acids is equal to 0.96. In the concentrate from antler skin, the maximum content (54.7%) of peptides with a low molecular weight of less than 2.9 kDa and up to 6.4 kDa was found using the molecular-weight distribution of peptide fractions.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):406-415
406-415
Brief communication
Physico-chemical characteristics of melanins culture medium Inocutis dryophila (Berk) Flasson & Niemela
Abstract
The purpose of the study was to investigate the effect of light treatment on the synthesis of endomelanins from the mycelium of Inocutis dryophila in a liquid culture medium. To identify the effect of light on the synthesis of melanins, the mycelium of Inocutis dryophila was cultivated in a liquid medium in the dark and using blue light treatment. As a result, two types of melanins IDM-1 and IDM-2 were obtained. It has been established that the light factor influences the quantitative release of melanins from the mycelium of Inocutis dryophila into the culture liquid. The use of blue light resulted in lower melanin content in the culture fluid than in the dark. Ultraviolet and infrared spectrometry showed that both types of melanins have typical spectra and graphs for fungal melanins. Infrared spectrometry showed that treatment of mycelium with blue light led to deformation of IDM-1. It was revealed that IDM-2 melanins exhibit greater antiradical activity than IDM-1 melanins. Thus, light treatment of Inocutis dryophila mycelium in a liquid medium affects the quantitative release of melanins into the culture liquid, promotes a change in the structure, as well as manifestation of a biological effect.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):416-420
416-420
Native organization of alternative NAD(P)H-dehydrogenases NDA and NDB in mitochondria of etiolated pea sprouts
Abstract
Numerous biochemical and structural studies into the native organization of oxidative phosphorylation in the mitochondria of various eukaryotic organisms have convincingly shown that respiratory complexes can associate with one another to form higher-order structures referred to as supercomplexes. Plant mitochondria are distinguished by a more complicated organization of the respiratory chain due to the presence of a number of alternative oxidoreductases. It is considered that these enzymes do not physically interact with those of the cytochrome pathway. However, the available literature data obtained on yeast mitochondria suggests the possibility of such an association. In this regard, we aimed to study the native organization of alternative NAD(P)H-dehydrogenases NDA and NDB in plant mitochondria. The work was performed on six-day etiolated pea seedlings. The 2D BN/SDS-PAGE in combination with immunochemistry found that, in pea organelles, the main part of the populations of NDA and NDB alternative NAD(P)H dehydrogenases were included in superstructures with masses of 700, 780, and 900 kDa. Additionally, NDA was detected in the region of 1480 and 1600 kDa, and NDB was registered at values of 1330, 340, and 100–120 kDa. An analysis of subunit profiles of the observed associations and a colorimetric detection of ATPase activity in 1D BN-gel suggested that the major part of the NDA and NDB populations identified by the available antibodies was associated with ATP synthase and represented a heterogeneous population of ATP-synthasomes, assumably, with a NDA2/NDB2Va/b1-2 composition. The rest of the enzymes were likely to be part of the NDA2/NDB2III2IV and NDA2IV1Va2 supercomplexes. The physiological significance of the association of alternative NAD(P)H dehydrogenases with ATP synthase requires further study.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):421-427
421-427
Synthesis of sodium 1,3-propanebis(dithiocarbamate) and study of its flotation properties
Abstract
Development and selection of a suitable reagent for efficient flotation is of great importance for ore beneficiation processes. Dithiocarbamates represent a class of organic compounds that are widely used as reagent-collectors in ore flotation. In this work, we conducted an analytical review of the methods currently used for obtaining this class of compounds and established the main method for obtaining dithiocarbamate salts to be the interaction of primary or secondary amines with carbon disulfide (CS2) in the presence of potassium or sodium hydroxide. The aim of the reviewed work was to synthesize sodium 1,3-propanebis(dithiocarbamate), as well as to study its flotation properties in the beneficiation of gold-bearing sulfide ores. A simple and effective method for sodium 1,3-propanebis(dithiocarbamate) synthesizing was proposed. Its structure was confirmed using physicochemical methods (infrared spectroscopy, 1H, 13C nuclear magnetic resonance spectroscopy). A set of studies found that the combined use of potassium butyl xanthate and sodium dialkyl dithiophosphate (BTF-1552) with sodium 1,3-propanebis(dithiocarbamate) led an increase in the efficiency of extraction of the target component of up to 81.63%, as well as an increase in its content in the concentrate of up to 7 g/t. In addition, the combination of sodium 1,3-propanebis(dithiocarbamate) with potassium butyl xanthate was shown to enable an extraction efficiency of 80.51%, as well as a valuable component content in the concentrate of up to 6.5 g/t with a low gold content in flotation tailings of 0.07 g/t. The proposed synthesis method and the results of flotation tests of gold-bearing ores are of interest for further research in the field of organic synthesis and practical application.
Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya. 2024;14(3):428-435
428-435