Addition Of Peroxide Research Articles

Electrocoagulation-Electro-Fenton hybrid system for dairy wastewater treatment: A comprehensive test and analysis, in aqueous solution

This study aimed to assess the efficacy of a treatment system combining electrocoagulation (EC) and Electro-Fenton (EF) for the remediation of the wastewater dairy industry. Synthetic samples simulating dairy effluent were prepared and subjected to characterization for turbidity, chemistry oxygen demand (COD), and pH. The Box-Behnken design, comprising operating parameters such as electric current (0.5 to 1.5 A), electrolysis time (5 to 17.5 min), initial pH (4.0 to 9.0), and hydrogen peroxide concentration (0 to 9.0 g/L), with three replications at the central point. The combined treatment was conducted in a batch reactor using iron electrodes and subsequently filtered using a qualitative filter paper. Analysis revealed the significance of electric current, electrolysis time, and peroxide concentration at a 5 % probability level for COD reduction. A reduction of 80 % in chemical oxygen demand (COD) and a 99 % reduction in turbidity were achieved by maintaining the original pH of the wastewater and using a combination of an electric current greater than 1 A and an electrolysis time of 11.5 min, without the addition of hydrogen peroxide. The results showed that the treatment followed the standards of the Brazilian legislation.

Efficient photocatalytic in-situ Fenton degradation of 2,4-dichlorophenol via anthraquinone-modified carbon nitride for 2e− oxygen reduction

Constructing a photocatalytic in-situ Fenton system (PISFs) is a promising strategy to address the need for continuous hydrogen peroxide (H2O2) addition and the low efficiency of H2O2 activation for hydroxyl radical generation in the traditional Fenton reaction. In this study, we constructed a photocatalytic in-situ Fenton system using anthraquinone-modified carbon nitride (AQ-C3N4) for efficient pollutant degradation. The resultant AQ-C3N4 not only enhanced the production of H2O2 but also increased the generation of hydroxyl radical (·OH). Experimental results demonstrated that, the apparent rate constant for the degradation of 2,4-Dichlorophenol (2,4-DCP) by AQ-C3N4-PISFs was 0.145 min−1, which is 2.74 times higher than that of C3N4 under visible light. Density functional theory (DFT) calculations indicate that AQ modification promotes electron-hole separation while increasing the adsorption energy of O2. Independent gradient model (IGM) analysis based on Hirshfeld Partition revealed that van der Waals interactions between AQ-C3N4 and 2,4-DCP promoted the degradation process. This work provides new ideas to overcome the problems of continuous addition of H2O2 and low utilization of ·OH that exist in conventional Fenton system.

Bioactivity of Amphidinol-Containing Extracts of Amphidinium carterae Grown Under Varying Cultivation Conditions.

Microalgae are of great interest due to their ability to produce valuable compounds, such as pigments, omega-3 fatty acids, antioxidants, and antimicrobials. The dinoflagellate genus Amphidinium is particularly notable for its amphidinol-like compounds, which exhibit antibacterial and antifungal properties. This study utilized a two-stage cultivation method to grow Amphidinium carterae CCAP 1102/8 under varying conditions, such as blue LED light, increased salinity, and the addition of sodium carbonate or hydrogen peroxide. After cultivation, the biomass was extracted and fractionated using solid-phase extraction, yielding six fractions per treatment. These fractions were analyzed using Liquid Chromatography-High-Resolution Mass Spectrometry (LC-HRMS/MS) to identify their chemical components. Key amphidinol compounds (AM-B, AM-C, AM-22, and AM-A) were identified, with AM-B being the most abundant in Fraction 4, followed by AM-C. Fraction 5 also contained a significant amount of AM-C along with an unknown compound. Fraction 4 returned the highest antimicrobial activity against the pathogens Staphylococcus aureus, Enterococcus faecalis, and Candida albicans, with Minimal Biocidal Concentrations (MBCs) ranging from 1 to 512µg/mL. Results indicate that the modulation of both amphidinol profile and fraction bioactivity can be induced by adjusting the cultivation parameters used to grow two-stage batch cultures of A. carterae.

Oxidative stress and culture atmosphere effects on bioactive compounds and laccase activity in the white rot fungus Phlebia radiata on birch wood substrate

Wood-decaying white rot fungi live in changing environmental conditions and may switch from aerobic to fermentative metabolism under oxygen depletion. Decomposition of wood and lignocellulose by fungi is dependent on enzymatic and oxidative biochemistry including generation of reactive oxygen species. In this study, we subjected semi-solid wood-substrate cultures of the white rot fungus Phlebia radiata to oxidative stress by addition of hydrogen peroxide under aerobic and anaerobic cultivation conditions. Wood decomposition and fungal metabolism were followed by analysis of extracellular organic compounds, mycelial growth, and laccase activity. Under both atmospheric conditions, accumulation of bioactive aromatic compounds from birch wood occurred into the culture supernatants after hydrogen peroxide treatment. The supernatants inhibited both fungal growth and laccase activity. However, the fungus recovered from the oxidative stress quickly in a few days, especially when cultivated under regular aerobic conditions. With repeated hydrogen peroxide treatments, laccase suppressive-recovery effect was observed. Culture supernatants demonstrated antioxidant and antimicrobial effects, in concert with emergence of chlorinated birch-derived organic compounds. Bioactivities in the cultures disappeared in the same pace as the chlorinated compounds were transformed and de-chlorinated by the fungus. Our results indicate tolerance of white rot fungi against excessive oxidative stress and wood-derived, growth-inhibiting and harmful agents.

Coaxial Bioprinting of Enzymatically Crosslinkable Hyaluronic Acid-Tyramine Bioinks for Tissue Regeneration.

Three-dimensional (3D) bioprinting has emerged as an important technique for fabricating tissue constructs with precise structural and compositional control. However, developing suitable bioinks with biocompatible crosslinking mechanisms remains a significant challenge. This study investigates extrusion-based bioprinting (EBB) using uniaxial or coaxial nozzles with enzymatic crosslinking (EC) to produce 3D tissue constructs in vitro. Initially, low-molecular-weight dextran-tyramine and hyaluronic acid-tyramine (LMW Dex-TA/HA-TA) bioink prepolymers were evaluated. Enzymatically pre-crosslinking these prepolymers, achieved by the addition of horseradish peroxidase and hydrogen peroxide, produced viscous polymer solutions. However, this approach resulted in inconsistent bioprinting outcomes (uniaxial) due to inhomogeneous crosslinking, leading to irreproducible properties and suboptimal shear recovery behavior of the hydrogel inks. To address these challenges, we explored a one-step coaxial bioprinting system consisting of enzymatically crosslinkable high-molecular-weight hyaluronic acid-tyramine conjugates (HMW HA-TA) mixed with horseradish peroxidase (HRP) in the inner core and a mixture of Pluronic F127 and hydrogen peroxide in the outer shell. This configuration resulted in nearly instantaneous gelation by diffusion of the hydrogen peroxide into the core. Stable hydrogel fibers with desirable properties, including appropriate swelling ratios and controlled degradation rates, were obtained. The optimized bioink and printing parameters included 1.3% w/v HMW HA-TA and 5.5 U/mL HRP (bioink, inner core), and 27.5% w/v Pluronic F127 and 0.1% H2O2 (sacrificial ink, outer shell). Additionally, optimal pressures for the inner core and outer shell were 45 and 80 kPa, combined with a printing speed of 300 mm/min and a bed temperature of 30 °C. The extruded HMW HA-TA core filaments, containing bovine primary chondrocytes (BPCs) or 3T3 fibroblasts (3T3 Fs), exhibited good cell viabilities and were successfully cultured for up to seven days. This study serves as a proof-of-concept for the one-step generation of core filaments using a rapidly gelling bioink with an enzymatic crosslinking mechanism, and a coaxial bioprinter nozzle system. The results demonstrate significant potential for developing designed, printed, and organized 3D tissue fiber constructs.

Models for Single‐Site Heterogeneous Catalysts on Carbon: MoO2 Epoxidation Catalyst Anchored to a Fullerene

Single‐site molybdenum dioxo catalysts, fullerenol/MoO2, are prepared via grafting precursor (DME)MoO2Cl2 onto a highly polyhydroxylated fullerene (ful) and a isomerically pure and well‐defined fullerene (ful*). These catalyst structures are characterized by ICP‐OES, XPS, XANES, EXAFS, DRIFT, Raman, and NMR spectroscopy, and DFT. Mo 3d5/2 XPS and Mo K‐edge XANES assign the oxidation state as Mo(VI). Mo EXAFS data fitting reveals two Mo=O double and two Mo‐O single bonds at distances of 1.7 and 1.9 Å, respectively, while an Mo=O stretchingl mode is observed at ~950 cm‐1 by DRIFT and Raman spectroscopy. These data align well with computational results, supporting the proposed catalyst structure as Fullerene(‐µ‐O‐)2M(=O)2. Additionally, DFT provides insight into the energetically favorable grafting sites for an isomerically pure fullerenol. The scope of fullerenol/MoO2 mediated alkene epoxidation includes abiotic alkenes, natural occurring terpenes, and conjugated olefins. For cyclooctene the rate law is first‐order in [Mo], near first order in [olefin] and zero‐order in [t‐butyl hydroperoxide]. A plausible reaction mechanism involves peroxide addition first and then cyclooctene addition directly across the peroxo bond forming the epoxide product, consistent with DFT computation. Overall, fullerenol/MoO2 shows promise as a sustainable and structurally well‐defined system with versatile catalytic activity and good epoxidation recyclability.

Selective detection of ketamine in human urine samples by electrochemiluminescence sensor based on conductive molecular imprinted polypyrrole: A hydrogen peroxide‐free electrochemiluminescence assay

AbstractA new sensor was fabricated for the determination of ketamine (Ket) in urine samples based on enhanced electrochemiluminescence (EECL) behavior of luminol on a carbon paste electrode (CPE) modified with the conductive molecularly imprinted polymer (CMIP) film. The FESEM technique was applied to demonstrate the rod shape morphology of CMIP. Unlike the common luminol system, EECL signal of luminol no need to addition of hydrogen peroxide and it might find application in efforts to avoid instability of hydrogen peroxide or its interference with the analytes of interest. The EECL emission has been optimized by an investigation of the applied potentials, electrochemical polymerization conditions, template and modifier concentrations, and the pH solution. Under the optimum conditions, the EECL signal depended linearly on the Ket concentration within a range from 0.1 to 1.25 μM with a limit of detection (LOD) of 0.08 μM. The sensor exhibited very good recovery percentages ranging from 92% to 101% in urine samples, while precisions were ≤3%. These results suggested that the proposed sensor would be applicable for analysis Ket in complex matrixes without interfering of other drugs (anesthetics) and thus has the potential to be used in clinical application.

High toughness and fast home-compost biodegradable packaging films derived from polylactic acid/thermoplastic starch/para-rubber ternary blends

This research aims to formulate biobased and biodegradable packaging films with high toughness and fast home-compost biodegradation using ternary blends of polylactic acid (PLA), Para rubber (NR), and thermoplastic starch (TPS) through blown-film extrusion. The TPS content in this work ranges from 5 to 20 wt%, while the PLA: NR ratio is fixed at 70:30. At this PLA: NR ratio, the blend with 10 wt% TPS (PNT10) exhibited the highest % elongation at break and tensile toughness. Peroxide radical initiator was investigated as a potential additive for improving the properties of the ternary blend. Our binary interaction study indicated that peroxide initiated grafting reactions of PLA–NR and NR–TPS pairs, while no grafting occurred between PLA and TPS. In ternary blends, the highest peroxide content (0.5 wt%) increased the % elongation at break up to 120%, with the tensile toughness reaching 7255 MJ/m3. The improved compatibility induced by peroxide addition was supported by enhanced dispersion of TPS in the PLA/NR matrices. Results from the room-temperature soil burial test indicated that the presence of TPS could significantly accelerate the home-compost degradation of PNT films compared to films produced from neat PLA and PLA/NR. This suggests its potential as both a cost reducer and a biodegradation accelerator.

Effect on polytropic index, performance and emission of diesel engine using hydrogen as gaseous fuel with additive di-tert butyl peroxide

Diesel engines are commonly used due to its higher reliability and better fuel conversion efficiency. However, it produces exhaust emissions like carbon dioxide (CO2) and particulate matter (PM). Hydrogen gas is regarded as a clean fuel as it is free from carbon. The addition of hydrogen fuel enhances the burning rates and extends the flammability limits of fossil fuels, and therefore has the potential of reduced exhaust emission in diesel engines operating on dual fuel mode. This paper has investigated the effect of hydrogen addition to the performance and emissions of a single-cylinder diesel engine, working in dual fuel mode with additive di-tert butyl peroxide (DTBP). About 25% hydrogen was introduced into the cylinder on a mass basis via the engine intake manifold with the addition of additive di-tert butyl peroxide up to 5% in diesel fuel. In this experimental study, mean gas temperature, indicated mean effective pressure (IMEP), brake mean effective pressure (BMEP), polytropic index, and exhaust emissions were studied at medium (53%) and high (69%) load conditions. The indicated mean effective and brake mean effective pressure was 9.79 bar with a 3% addition of additive and 4.15 bar with the 5% addition of additive as compared with 8.71 bar and 4.11 bar diesel fuel operation. 16% hydrogen addition with 1% di-tert butyl peroxide, IMEP, and BMEP are 10.92 bar, and 4.14 bar respectively.

Exploring innovative strategies for precipitation extent enhancement in a downscaled Bayer process tank

AbstractThe Bayer process is a cornerstone of alumina production, and its precipitation stage holds the key to both efficiency and product quality. In this study, we embarked on a comprehensive exploration of strategies to enhance the precipitation extent of aluminium hydroxide, a pivotal step in the Bayer process. Utilizing a newly constructed reactor, along with experiments using reactors in series, we rigorously experimented with various factors, including the addition of hydrogen peroxide (H2O2) as an enhancer, seed activation methods, the integration of a hydrocyclone within the processing unit, the application of a magnetic field, and the injection of supersaturated liquor midway through the process. These diverse strategies were systematically assessed to decipher their individual and synergistic effects on precipitation extent. Our research aims to uncover the optimal conditions for maximizing alumina precipitation while maintaining product quality and seed particle stability. By offering new insights and practical solutions, this study contributes to the ongoing advancement of alumina production within the Bayer process.

Estimating biofilm activity on biofilter elements in recirculating aquaculture systems (RAS) for rearing Atlantic salmon parr (Salmo salar) during operation with ozone and peracetic acid

Chemical disinfection in a recirculating aquaculture system (RAS) may affect biofilm-associated bacteria and the nitrification performance in the biofilter units. The biofilm response to chemical disinfectants in RAS remains unclear, but it can be understood using methods to quantify biofilm activity. Here, we compared the effects of two disinfection strategies, continuous ozone at 0.06 mg/L Cl2 equivalent (Ozone group) and peracetic acid (PAA) at 1 mg/L (PAA group) to control group without disinfectant, on biofilm activity on biofilter elements from nine identical experimental RAS with Atlantic salmon parr (Salmo salar) during a four-week trial. Biofilm activities on biofilter elements from the three groups were examined by measuring oxygen consumption rates (OCR) following sequential spiking with pure tap water, and tap water spiked with nitrite or ammonium, as well as oxygen release rate (kor) following hydrogen peroxide (H2O2) addition, to estimate metabolic activities of biofilm related to endogenous respiration and substrate turnover. The results show that the applied PAA dose increased the endogenous respiration activity of biofilm by 39–133%, stimulated the rate of biofilm enzymatic decomposition of H2O2 by 135%, and partially impaired the biofilm metabolism for nitrite oxidation (decrease by 36%), resulting in a significant nitrite accumulation (rise by 59%) in the cultured water, compared to control over experimental period. Ozone treatment caused an enhanced endogenous respiration activity of biofilm at the beginning of the experiment (increase by 45–74%), but dropped to control levels at the end of the experiment. The results indicate that chronic exposure to PAA can alter the metabolic state of biofilm, which can have consequences for biofilter functions, while chronic exposure to ozone improved water clarity without compromising the metabolic status of biofilm. The investigations provided insights into biofilm response to chemical disinfectant in RAS, which would benefit the optimization of an effective and safe use of disinfectants in RAS.

Experimental study on the ignition delay characteristics of pyrolysis gas from kerosene with hydrogen peroxide addition

The ignition issue of the hypersonic aircraft remains a challenging task due to the extremely short residual time of milliseconds. To study the potential candidate of hydrogen peroxide for ignition enhancement, the ignition delay times of pyrolysis gas with the addition of 0–5000 ppm hydrogen peroxide were experimentally measured and quantitatively analyzed at temperatures of 833.8–962.1 K, equivalence ratios of 0.5–1.5, pressures of 31.9–48.8 bar, and the dilution of 45 vol% Ar. A novel injection system based on a Laval nozzle was designed to well atomize and evaporate the liquid hydrogen peroxide. The experimental results showed that the enhancing effect of hydrogen peroxide was proceeded by three stages, in which the decreasing efficiency gradually weakened with the increase of additive fraction. The ignition delay times of pyrolysis gas dramatically shortened by 66.1 % with 1000 ppm of hydrogen peroxide. Only a decrement of 19.1 % was obtained as the additive fraction increased from 1000 to 4000 ppm. The decline at 4000–5000 ppm even reduced to 2.0 %. It is suggested to add no more than 1000 ppm of hydrogen peroxide from the perspective of the highest acceleration efficiency on the ignition delay times of pyrolysis gas.

Combined use of versatile peroxidase and aryl alcohol oxidase of Pleurotus eryngii to decolorize melanin on the skin

Melanin plays an important role in protecting skin cells from harmful UV radiation, but its uneven pigmentation in the skin sometimes demands cosmetic resolution. As a safe and effective way of evening the skin tone, enzymatic decolorization of melanin at the stratum corneum has been proposed. In this regard, the use of lignin peroxidase, in the presence of hydrogen peroxide and veratryl alcohol, an electron mediator, has been explored. Here, we first show that versatile peroxidase (VP) and aryl alcohol oxidase (AAO) purified from the Pleurotus eryngii liquid culture can be used to decolorize melanin without exogenous hydrogen peroxide. This resembles the oxidative degradation pathway of lignin in nature; AAO generates hydrogen peroxide from veratryl alcohol, and VP utilizes generated hydrogen peroxide while using veratryl alcohol as a mediator. We further explored the use of POX_Pe, the crude peroxidase preparation of the Pleurotus eryngii liquid culture, for melanin decolorization because of its better stability. Using POX_Pe and veratryl alcohol, over 60 % of melanin decolorization was obtained in 1 h in the absence of exogenous hydrogen peroxide addition. Furthermore, POX_Pe could decolorize melanin in a 3D human pigmented epidermis model, demonstrating its possible applications in cosmetics.

Oczyszczanie i waloryzacja ścieków z wytłoczyn z oliwek

Wastewater generated during the production of pomace olive oil is complex and highly variable due to different cultivation and processing characteristics. It has a high toxic organic load, low pH, and high chemical and biological demands. To reduce the concentration of chemical oxygen demand (COD) and total phenolic compounds (TPh) in pomace olive oil wastewater, several treatment processes have been studied. These include: (i) coagulation/flocculation, (ii) electrocoagulation, (iii) peroxy-electrocoagulation, (iv) electrochemical peroxidation, (v) Fenton, (vi) electro-Fenton, (vii) photo-Fenton, and (viii) adsorption. Coagulation/flocculation and electrocoagulation resulted in a maximum COD removal of 16%, while techniques involving the addition of hydrogen peroxide (iii-vii) had an average of 78% TPh removal but only 20% COD removal. Adsorption resulted in a maximum of 29% COD and 75% TPh removal. None of the tested techniques were able to remove more than 50% of COD, indicating the difficulty of removing organic matter in this effluent. However, advanced oxidation techniques were effective in degrading phenolic compounds, although they required relatively high dosages of oxidant.

Removal of Phenols fromSynthetic Wastewater byHorseradish Peroxidase(HRP)

Plant peroxidase has a solid potential to remove phenol from wastewater. However, large-scale use of these enzymes for phenol removal requires a source of cheap, abundant, and easily accessible peroxidase-containing material. In this study, the horseradish peroxidase(HRP)removes the phenolic compound from the phenolic environment. The enzymatic method was used to show a reduction of toxicity between the treated and untreated phenolic solution. The HRP, with the addition of hydrogen peroxide (H2O2), reacted with the phenolic compound and produced a treated solution containing about 20% of phenol compared to the initial acidic solution. The concentration of the treated solution was then determined using UV-Vis and FTIR spectroscopy. The effects of treating the acidic solution with HRPenzyme and H2O2were studied. The HRPenzyme decreases the amount of phenol present in an acidic solution by 80 %. The most effective concentrations for treating the acidic solution were HRPat 1.0 M and 1.0 M of H2O2at neutral pH.

Boosted photo-self-Fenton degradation activity by Fe-doped carbon dots as dual-function active sites for in-situ H2O2 generation and activation

Photo-Fenton process is acknowledged for its high efficiency and technical feasibility in water treatment; however, its application is constrained by the addition of iron ions and hydrogen peroxide (H2O2). Herein, an efficient photo-self-Fenton system with coating Fe-doped carbon dots (Fe-CDs) on the surface of highly crystalline C3N5 (HC-C3N5) nanosheets was developed for degradation of tetracycline (TC) under visible light irradiation. Experimental results reveal that Fe-CDs not only serve as active sites for facilitating superior light-induced charge separation and transfer towards the in-situ generation of H2O2 over HC-C3N5, but also provide the solid-phase Fe species for maximizing the activation of in-situ generated H2O2 to produce highly oxidative OH and O2– species towards the photo-self-Fenton reaction. This research presents a novel design approach of utilizing a Fe-CDs-based photo-self-Fenton system for efficient wastewater treatment.

Viscosity reduction of xanthan gum through free radical mechanisms mediated by ascorbic acid

Xanthan gum (XG) is a widely used thickener known for its high viscosity and excellent stability. However, the presence of ascorbic acid (AA) leads to a clear decrease in its viscosity, thereby affecting the application of xanthan gum in food products containing AA. Therefore, the aim of this study was to uncover the mechanism by which AA reduces the viscosity of xanthan gum. Ascorbic acid (0.1 mmol/L) caused a viscosity loss reaching up to 96% for xanthan gum solutions (2 g/L). The reaction was further enhanced by heating at 60 °C for 1 h without stirring, a weakly acidic system at pH 5.4, and the addition of hydrogen peroxide or metal ions (Fe2+ and Cu2+). Interestingly, AA induction produces free radicals and changes in their content correlate with a decrease in XG viscosity. Moreover, removing dissolved oxygen by heating and nitrogen purging treatment effectively reduced AA-derived free radical levels and prevented the decrease in XG viscosity. The decrease in viscosity of XG caused by AA involved its free radicals generated through an oxygen-dependent pathway.

Leaching of gold ore using creatine monohydrate

Creatine was used as a lixiviant for gold dissolution from gold ore. The effects of creatine concentration, temperature, leach time, and pH were examined for their influence on extent of gold dissolution. The results show that at a temperature of 75°C and pH 11.5, gold dissolution increased from 51% to 88% on increasing creatine concentration from 25 to 50 g/t. Further increase in creatine concentration showed a negative effect on the gold dissolution. Gold dissolution increased from 47% to 87% by increasing the temperature from 25°C to 55°C, and from 61% to 89% by increasing pH from 10 to 11.5. Under the optimum conditions of solids' content of 30%, pH 11.5, creatine concentration of 100 g/t, temperature of 75°C, and hydrogen peroxide addition of 2%, about 90% of the gold could be dissolved from the ore after 24 h. A comparison between creatine and cyanide leaching showed that 90% gold dissolution was achieved at a cyanide concentration of 300 g/t, which is three times higher than the creatine concentration under optimal conditions.

Hydrogen Peroxide May Reduce the Risk for Revision Surgery and Infection in Primary Shoulder Arthroplasty: Two-year Follow-up From a Prospective, Blinded, Controlled Trial.

The purpose of this study was to determine whether the addition of hydrogen peroxide to the preoperative skin preparation for primary total shoulder arthroplasty is associated with a difference in patient-reported outcomes, risk for postoperative infection, and risk for revision surgery at a minimum of 2-year follow-up. This was a prospective, blinded, and controlled trial, which included a consecutive series of patients undergoing primary shoulder arthroplasty. The control group underwent standard sterile skin preparation using ethyl alcohol and ChloraPrep applicators, and the peroxide group had the same preparation with the addition of hydrogen peroxide between the alcohol and ChloraPrep applications. We then compared patient-reported outcome scores (American Shoulder and Elbow Surgeons Shoulder Score [ASES], simple shoulder test [SST], visual analog scale [VAS]), infections, and revision surgeries between the two groups at 2-year follow-up. Of the 61 patients included in the original study, 52 of 58 (85%) living patients agreed to participate in this study. No preoperative differences were observed between groups. No difference was observed in ASES, SST, or VAS scores at 2 years. More revision surgeries were done in the control group (7 versus 2, P = 0.268) and Cutibacterium acnes infections (2 versus 0, P = 0.168). The addition of hydrogen peroxide to the preoperative skin preparation before primary shoulder arthroplasty is safe, and additional research is warranted to investigate whether it may decrease the risk for revision surgery and postoperative C acnes infection. III.

О СУБСТРАТНОЙ СПЕЦИФИЧНОСТИ И НЕКОТОРЫХ СВОЙСТВАХ ВНЕКЛЕТОЧНОЙ ОКСИДАЗЫ ИЗ БАЗИДИОМИЦЕТА NEONOTHOPANUS NAMBI

An extracellular enzyme with oxidase activity was isolated from the mycelium of the higher fungus Neonothopanus nambi by mild treatment of the biomass with β-glucosidase. A substrate specificity and some properties of the isolated extracellular oxidase were studied in the present work. Experiments revealed that the extracellular oxidase exhibited activity with most phenolic compounds chosen as model substrates. It is important to note that the enzyme exhibited a catalytic function in the reactions without the addition of exogenous hydrogen peroxide and other mediators. The highest catalytic activity of the enzyme was observed with veratryl alcohol and dihydric phenols, hydroquinone and guaiacol. The enzyme showed lower activity with aromatic azo compounds (ABTS, DAB, o-dianisidine). In reactions with dihydric phenol resorcinol and monophenol, the enzyme efficiency was extremely low. The kinetic parameters of the enzymatic reactions with actively oxidized substrates were determined. The addition of a divalent metal ion chelator (EDTA) did not affect the activity of the enzyme, while the addition of the SH reagent (DTT) increased the catalytic efficiency of the studied oxidase. The totality of the data obtained indicates that the extracellular oxidase of the N. nambi fungus catalyzes the oxidation of a wide range of aromatic compounds under slightly acidic and neutral conditions without the addition of additional mediators (in particular, hydrogen peroxide). This creates the prerequisites for studying the applicability of the enzyme in biomedical analytics.