Chemistry and Materials Science

Abstract: Herein, we report a simple physical mixture of chromenone and pyrazole as a cost-effective dual-channel fluorescent probe for selective detection of Fe³⁺ and Cr⁶⁺. The mixture exhibits typical aggregation-induced emission (AIE) behavior in both tetrahydrofuran (THF)/water and THF/simulated body fluid (SBF) systems, with maximum fluorescence intensity at 80% poor solvent fraction. The mixture maintains good AIE performance in physiological SBF medium, demonstrating potential for biomedical applications. Upon screening 18 metal ions (Ag⁺, Al³⁺, Au³⁺, Ba²⁺, Ca²⁺, Cr³⁺, Cr⁶⁺, Cu²⁺, Fe³⁺, Hg²⁺, Mo⁶⁺, Mg²⁺, Mn²⁺, Na⁺, Ni²⁺, Pb²⁺, Pd²⁺, Zn²⁺), two distinct selective responses were observed. In the UV-vis absorption channel, Fe³⁺ induces the most significant absorbance enhancement at 365 nm (∼3.5-fold), followed by Cr⁶⁺ (∼2.5-fold). In the fluorescence emission channel (λₑₓ = 310 nm), only Cr⁶⁺ triggers a unique and remarkable red-shift of the emission peak (∼10 nm), while all other metal ions cause negligible spectral changes. This wavelength-shift-based recognition mechanism is free from interferences such as probe concentration and light-source fluctuations, providing a physical basis for ratiometric detection. The differentiated responses of Fe³⁺ and Cr⁶⁺ in two optical channels offer a novel, low-cost fluorescent probe strategy for environmental monitoring and biomedical diagnosis.

Abstract: The aim of the study was to determine the influence of the application of different types of essential oils in the preparation of white brine cheese with the addition of es-sential oils in different concentrations on the organoleptic, physicochemical and bio-chemical indicators and assessment of the fat fraction. White brine cheese was ob-tained by the standard method and six concentrations of essential oils were used to determine the optimal dose of the additive. The organoleptic indicators of the cheese have the best ratings at 0.75 and 1% mint oil, 0.5 and 0.75% thyme, 0.5 and 0.75% ore-gano, 0.75% rosemary, 0.5% lemon balm, 0.5% basil and 0.75% turmeric and black pepper oil /3:1/. The use of essential oils increases the fat and protein content in the brine cheese at 24 h, but after ripening and storage for 6 and 12 months, the influence of the ongoing lipolysis and proteolytic changes was established, as a result of which both indicators decreased. The use of different types of essential oils in 6 concentra-tions reduces the antioxidant activity of white brine cheese by 8 to 10 times, while the total polyphenols increase by 4-5 times. Saturated fatty acids decrease with the addi-tion of mint, oregano, rosemary, lemon balm, basil to 1.5% (P≤0.001), and increase with thyme and turmeric with black pepper (P≤0.001) at the expense of unsaturated / mono and polyunsaturated / fatty acids (P≤0.001).

Abstract: The present paper aimed to study the effects of 40% ethanolic extracts (5 mg GAE/mL) from Ajuga reptans (Ajre), Geranium phaeum (Geph) and Helianthemum nummularium (Henu) on mouse normal fibroblasts and human blood mononuclear cell lines L929 and SC, as well as in silico ADMET and molecular docking assessments of the major and key phenolics found in the three test medicinal species, against the widespread protein disease cyclooxygenase 2 (COX-2), in comparison with the native ligand diclofenac. Briefly, in silico studies revealed flavonoid derivatives as being more likely to induce metabolic effects in humans, by interfering with the activity of cytochrome P450 (CYP450) isoenzymes, of P-glycoprotein transporters (P-gp), and of potassium channels (hERG) respectively, at the same time more effective inhibitors of COX-2 in comparison with phenolic acids. In vitro studies on Ajre indicated augmented inhibitory effects on the viability of L929 (IC₅₀ = 184.70 µg GAE/mL) and SC (IC₅₀ = 91.30 µg GAE/mL); Geph did not affect the viability of L929 (IC₅₀ = 414.70 µg GAE/mL) and showed putative effects on SC (152.00 µg GAE/mL); Henu revealed weak inhibitory effects on L929 (IC50 = 350.00 µg GAE/mL) versus high stimulatory effects on the viability of SC line (IC₅₀ = 183.50 μg GAE/mL), up to 21% more intense than those induced by LPS positive control.

Abstract: Linde Type A (LTA) zeolite was synthesized from purified Angren kaolin (Uzbekistan) by a metakaolin route. Raw kaolin was beneficiated by dispersion–decantation to reduce iron, calcined at 700 °C, and crystallized in NaOH solution at 100 °C. Products were characterized by powder X-ray diffraction (PXRD), X-ray fluorescence (XRF), Raman spectroscopy, N₂ physisorption and thermal analysis (TGA/DTA). PXRD confirmed crystalline LTA as the major phase (cubic lattice parameter a = 24.68 ± 0.02 Å), with residual quartz from the precursor. XRF gave a near-ideal bulk composition (Si/Al = 1.07, Na/Al = 0.98), confirming sodium incorporation, and Raman corroborated minor quartz and anatase impurities. The low N₂ BET area (~2.5 m² g⁻¹) reflects restricted access of the 4 Å LTA windows to N₂ at −196 °C rather than absence of microporosity. Thermogravimetric analysis showed a ~13 wt% loss of zeolitic water below 300 °C, confirming a hydrated microporous framework. Locally sourced Angren kaolin can thus be converted into crystalline LTA, a candidate material for gas-separation and ion-exchange applications.

Abstract: Hectorite intercalated with octadecyl trimethylammonium ions was synthesized with one-pot synthesis and the octadecyl trimethylammonium modified hectorite was used as adsorbent to remove phenol from aqueous solution. The pH and content of adsorbent were studied to obtain optimized condition to the adsorption of phenol. As for the 50 ml of 100 mg/L initial phenol solution at pH 12, the phenol removal rate attains about 92.3% when 0.5 g adsorbent is used. As for the adsorption isotherm, the Langmuir and Freundlich model were appropriate. The adsorption kinetic was in accord with the pseudo-second-order and the activation energy (Ea) was about 11.15 kJ/mol. The modified hectorite could be recycled and reused, maintaining a high adsorption amount after five times.

Abstract: Cellulose crystallinity is frequently associated with lignocellulosic biomass digestibility, yet its development during multistep biorefinery processing and its relationship with enzymatic hydrolysis remain difficult to isolate. This study investigated the evolution of cellulose crystallinity in wheat straw (Triticum aestivum) during Hot-Water Pretreatment (HWP), Water Pretreatment (WP), Organosolv extraction, sequential washing, and drying, and related these changes to enzymatic glucose yield. Crystallinity was determined using X-ray diffraction and an ATR-FTIR-based PLS model, while enzymatic hydrolysis was evaluated by HPLC-based glucose quantification. HWP caused a temperature-dependent decrease in crystallinity from 47.5 ± 1.3% in untreated straw to 27.0 ± 2.2% at 120 °C, whereas WP at room temperature caused no significant change. However, without subsequent Organosolv extraction, both pretreatments alone resulted in low glucose yields of approximately 10%, indicating that cellulose crystallinity is only one of several factors governing enzymatic hydrolysis efficiency. During washing after Organosolv extraction, crystallinity increased from 40.6 ± 2.1% to 54.2 ± 1.3%, while glucose yield was more closely associated with residual ethanol under the tested conditions rather than by crystallinity changes. Drying had the strongest effect, increasing crystallinity by up to 53,6% relative to the wet state. Overall, cellulose crystallinity should be considered as one of several interacting factors governing enzymatic digestibility, and sample moisture history must be carefully controlled when comparing crystallinity data.

Abstract: This study presents a comparative analysis of the effect of the structural-mineralogical type of clay matrices on the phase and structure formation in composite aluminosilicate materials within the multi-component Fe-Al-C-Si system. Highly plastic Saryozek montmorillonite clay and moderately plastic Alekseevskaya kaolinite-illite clay were investigated as binding matrices to consolidate iron-aluminosilicate fly ash from the Almaty CHPP-2. The raw materials and binary batches containing 10 to 50 wt.% fly ash were evaluated using XRD, XRF, TG/DTA, and SEM techniques. The results demonstrate that the superior plastic and binding properties of the Saryozek clay ensure enhanced consolidation of the non-plastic, fragmented ash particles. Simultaneous thermal analysis reveals that increasing the compaction pressure from 20 to 30 MPa induces a kinetic shift in the montmorillonite dehydroxylation interval toward higher temperatures (580 °C –720 °C) due to increased partial water vapor pressure within the dense green body. This thermal shift scientifically necessitates introducing an isothermal dwell at 600°C to mitigate firing defects. The optimal composite properties are achieved at a molding pressure of 30 MPa, a firing temperature of 1050 °C, and a fly ash concentration of 10–20 wt.%, yielding a peak compressive strength of 38.4 MPa. SEM analysis confirmed that under these conditions, the locally formed silicate melt uniformly encapsulates the crystalline mullite and quartz microparticles, whereas increasing the ash content to 50 wt.% results in a loose, highly porous structure that degrades strength down to 17.9 MPa. These findings lay a scientifically substantiated foundation for optimizing composite ceramic synthesis and reducing structural defects.

Abstract: Bio-derived functional materials are key platforms for long-term sustainable environmental remediation. Pine wood fibres (WF) is an abundant and renewable material with functional properties suited to specialized applications, including a high density of hydroxyl groups at its surface and mechanical toughness imparted by the lignin fraction. In the present work, monometallic and bimetallic nanoparticles (NPs) of first series transition metals, Fe, Co, Cu and Fe/Cu were immobilized onto original WF and WF treated with NaOH (WF_N). The prepared WF-supported NPs were characterized by SEM/EDS, XPS, XRD and FTIR-ATR and evaluated in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol in aqueous solution, at room temperature, by NaBH4. Copper-based materials exhibited superior catalytic efficiency, with the NaOH pre-treatment yielding shorter induction times and enhanced stability. For material WF_NCu, 97 % of 4-NP reduction was achieved in 3 minutes with a rate constant of k1 = 2.209 min-1. This material was used for five successive cycles with no decrease in 4-NP reduction efficiency, being easily recovered from reaction media.

Abstract: This study investigates the development and evaluation of Debina white wine products with varying levels of sulfur dioxide, enriched with saffron, mastic, and mountain tea, aiming to enhance their functional properties and to assess the impact of these plant-derived additives on physicochemical, antioxidant, bioactive, and sensory characteristics. Analyses were performed, including sulfur dioxide determination, absorbance at 420 nm, total phenolic content, and free sulfhydryl groups, antioxidant activity assays, bioactivity evaluation, volatile compound profiling, and sensory analysis. The results demonstrated improved preservation of sulfur dioxide, phenolic compounds, antioxidant capacity, and anti-inflammatory activity in the enriched wine samples compared to controls throughout storage. Additionally, the wines were enriched with volatile compounds characteristic of the added plant materials. Sensory evaluation indicated that the products were organoleptically acceptable, while oxidation sensory perception during storage was lower than in the control samples. Overall, the findings suggest that saffron, mastic, and mountain tea can be effectively utilized in wines with reduced sulfur dioxide levels, as they enhance oxidative stability and contribute to the preservation and functional quality of the final product.

Abstract: [¹¹C]Choline ([¹¹C]CHO) has reemerged as a radiopharmaceutical tracer for positron emission tomography (PET) diagnostics and optimized synthesis setups are thus needed to meet the increased demand, often on existing production lines. Originally, [¹¹C]CHO has experienced a decline in use for PET diagnostics, particularly in prostate cancer imaging due to radiopharmaceuticals with higher target specificity. However, recent studies have demonstrated superior sensitivity and diagnostic accuracy of [¹¹C]CHO for localizing autonomous adenomas in primary hyperparathyroidism (PHPT) compared to conventional ⁹⁹ᵐTc-sestamibi scintigraphy. The PET-scan is used prior to surgery, but not for the diagnosis of PHPT. The patient compliance is high due to the relatively short time in the scanner. With this renewed clinical relevance, optimization of [¹¹C]CHO synthesis is warranted, as standard production protocols typically yield only 2.5–3.0 GBq. In this study, three critical steps in the synthesis process on a TracerMaker module were systematically evaluated and optimized. (1) Extending the irradiation time from 25 to 42 minutes produced no significant increase in radiochemical yield (RCY). (2) Increasing the precursor, dimethylaminoethanol (DMAE) loading volume to 150 µL divided across two serially connected Sep-Pak Accell CM Plus Light cartridges resulted in a twofold RCY increase but also elevated residual DMAE levels in the final product. (3) Increasing washing volumes of ethanol and water did not improve purification efficiency; however, replacing the two stacked cartridges (2 × 130 mg) with a single cartridge containing a higher sorbent mass (360 mg) achieved effective DMAE removal while maintaining high RCY. These findings demonstrate a practical route for optimizing [¹¹C]CHO synthesis to meet the growing clinical demand of [¹¹C]CHO for imaging of PHPT.

Abstract: The growing demand for efficient and sustainable materials for air purification has stimulated interest in activated carbons derived from renewable biomass resources. In this study, activated carbons were prepared from rice husk, wheat straw, sawdust, and walnut shells and systematically investigated as sorbents for toxic gases and volatile organic compounds. The materials were characterized using nitrogen and water vapour sorption isotherms, scanning electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray analysis to evaluate their textural properties, morphology, thermal stability, and surface chemistry. The results showed that the precursor type strongly influences the pore structure and functional group composition of the activated carbons. Wheat straw and Rice husk–derived activated carbons exhibited the highest total pore volume and a well-developed porous structure, together with a high content of oxygen- and silicon-containing elements. Gas breakthrough experiments with different probes showed that wheat straw–derived activated carbon excels in VOC removal due to its highly microporous structure. In contrast, rice husk–derived activated carbon displays strong affinity toward inorganic gases such as NH₃ and, after urea modification, achieves enhanced performance for SO₂. These results underscore the versatility and practical applicability of carbon materials obtained from plant residues.

Abstract: A multi-analytical study was conducted to investigate the deterioration mechanisms affecting the stone materials of the Arca di Cansignorio della Scala (Verona, Italy) and to identify the residual traces of polychromy and gilding. The investigation combined macroscopic mapping, stratigraphic sampling, optical microscopy (OM), environmental scanning electron microscopy (ESEM) coupled with energy-dispersive spectroscopy (EDXS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and ion chromatography (IC). The monument, mainly carved in Candoglia marble, exhibits three principal weathering typologies: (i) meteoric washing associated with marble decohesion, (ii) grey deposits (dirt accumulation areas); and (iii) sulphation-related black crust formation (dirt wetting areas). In addition, severe mechanical damage is as-sociated with early 20th-century structural consolidation using embedded iron bars, whose corrosion-induced volumetric expansion generated vertical fissures. Strati-graphic analyses revealed the presence of original azurite-based polychrome, proteina-ceous and lipidic binders, lead white preparatory layers, and multiple gold leaf applica-tions of gold leaf. The study highlights the interaction between environmental exposure, atmospheric pollution, material incompatibility resulting from past restorations cam-paigns, and the preservation state of the surviving decorative painted layers.

Abstract: The escalating global crisis of water scarcity, exacerbated by the increasing prevalence of heavy metal contamination from anthropogenic activities, necessitates the development of innovative and sustainable remediation technologies. Recognizing the inherent metal-binding capabilities of Cannabis sativa L. (hemp), this study introduces a novel approach for copper(II) ion removal from aqueous solutions. We investigated the synergistic potential of combining hemp-derived cannabinoids with chitosan-polyvinyl alcohol (PVA) hydrogels to create a bio-based adsorbent. Hemp oil, rich in cannabinoids, was incorporated into chitosan-PVA hydrogels synthesized to enhance mechanical stability. The resulting hemp hydrogels (HHGs) were characterized using Fourier Transform Infrared Spectroscopy (FTIR), confirming the integration of the oil within the hydrogel matrix. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis of copper-contaminated solutions treated with HHGs over 24 hours demonstrated a reduction in copper ion concentration, suggesting a biosorption mechanism. Swelling studies revealed an inverse relationship between hemp oil content and water uptake capacity. Thermal studies showed excellent stability amongst gel types. This work establishes the feasibility of utilizing hemp-modified hydrogels as a promising avenue for heavy metal removal, paving the way for future optimization of these bio-composites in both drinking water purification and industrial wastewater treatment applications.

Abstract: Surface modification of zinc oxide nanoparticles (ZnO NPs) with organosilane capping agents represents an effective strategy to control their physicochemical and biological properties. In this work, we report for the first time the use of halogenosilanes, namely (3- chloropropyl)trimethoxysilane (CPTMS), (3-bromopropyl)trimethoxysilane (BPTMS) and (3-iodopropyl)trimethoxysilane (IPTMS), for the surface functionalization of ZnO NPs obtained by chemical precipitation. Structural and morphological characterization (PXRD, TEM, SEM-EDX and FTIR) confirmed successful surface modification and revealed a significant particle size reduction from ~31 nm for unmodified ZnO to ~8 nm for BPTMS-modified ZnO (ZnO_b). The biological evaluation showed that halogenosilane-modified ZnO NPs exhibit enhanced cytotoxic activity against prostate cancer cell lines (PC3 and 22Rv1), with ZnO_b displaying the highest activity, likely associated with improved cellular uptake and increased reactive oxygen species (ROS) generation. In contrast, antimicrobial assays revealed only moderate bactericidal effects against Escherichia coli and Staphylococcus aureus at relatively high concentrations (≥1250 µg mL⁻¹), while no significant activity was observed against Pseudomonas aeruginosa, Burkholderia contaminans or Candida spp. within the tested range. These findings suggest that halogenosilane functionalization modulates the biological profile of ZnO nanoparticles by enhancing anticancer effects while also influencing microbiocidal activity, highlighting the role of surface chemistry in tuning biological selectivity. The present study supports the concept that rational surface engineering of ZnO-based nanoplatforms can be exploited to favor tumor-targeted activity over broad-spectrum antimicrobial effects, providing new perspectives for the design of application-oriented nanomaterials.

Abstract: Rapid detection and localization of liquid fuel spills is critical for first responders assessing fire and health hazards, yet current methods require ground-based sampling or specialized instrumentation, limiting their practicality for wide-area emergency response. We present a drone-based passive colorimetric sensor system using test strips impregnated with Nile red, similar to colored confetti. Nile red is a solvatochromic dye that undergoes distinct visible color transitions upon exposure to different liquids. The dye is embedded within a polymer matrix that minimizes leaching while providing high optical contrast between dry, water-exposed, and fuel-exposed states. The sensor strips exhibit solvent-specific colorimetric responses within one minute of exposure, readily detectable by standard RGB cameras mounted on unmanned aerial vehicles (UAV) at altitudes up to 50 m. Automated classification was validated at 20 m altitude, enabling remote surveillance of contaminated surfaces without specialized equipment. Color-corrected image analysis using Calibrite ColorChecker calibration ensures reliable interpretation under variable field illumination (625–77,000 lux). Systematic laboratory evaluation of twelve fossil and bio-derived fuels revealed characteristic hue shifts that clearly discriminate ethanol-containing gasoline blends from diesel-range fuels. Field validation confirmed localization and classification of fuel-exposed sensors, achieving F1 scores of 0.94 for gasoline and 0.98 for diesel detection with no false positives in the tested scenarios. This cost-effective and scalable approach provides actionable information on both contamination location and fuel type, crucial for rapid hazard assessment in emergency response scenarios.

Abstract: Whether copper fundamentally alters Mo-centered redox thermodynamics or mainly tunes hydrogen adsorption in Ni–Mo electrocatalysts under alkaline hydrogen evolution reaction (HER) conditions remains unresolved. Density functional theory calculations combined with a field-corrected computational hydrogen electrode framework are used to evaluate the thermodynamic stability of H₃Mo, H₃MoOH, H₂Mo(OH)₂, and MoO(OH)₃ on Cu(111) and Ni(111) and to construct surface Pourbaix diagrams under electrochemical conditions. The results show that substrate identity reorganizes the redox stabilization hierarchy of these Mo intermediates. Across the examined conditions, at least one of H3Mo, H3MoOH, or MoO(OH)₃ is thermodynamically favored over H₂Mo(OH)₂ on both surfaces. However, only Cu(111) exhibits measurable pH-dependent free-energy shifts, reaching 0.28 eV on the reversible hydrogen electrode scale. The magnitude of this electrostatic modulation is comparable to the intrinsic substrate-dependent relative Gibbs free-energy differences, suggesting that Cu reshapes Mo redox thermodynamics rather than merely weakening hydrogen binding strength. Electronic structure and vibrational analyses further show that Cu(111) preferentially weakens Mo–O interactions, whereas Ni(111) more strongly perturbs Mo–H bonding in hydrogen-rich complexes. Overall, these results establish that substrate identity governs the electrostatic modulation of Mo redox thermodynamics under alkaline HER conditions and provide a mechanistic insight into substrate effects relevant to Cu-containing Ni–Mo systems.

Abstract: The Fenton reaction remains one of the most widely investigated advanced oxidation processes for wastewater treatment due to its ability to generate highly reactive oxygen species capable of degrading persistent organic pollutants. However, classical homoge-neous Fenton systems suffer from significant limitations, including narrow pH applica-bility, iron sludge generation, and poor catalyst reusability. In response, extensive research has been devoted to the development of heterogeneous and advanced Fenton-like catalysts that address these challenges while improving catalytic efficiency and operational stabil-ity. This review provides a comprehensive analysis of the evolution of Fenton catalysis, from classical homogeneous systems to modern advanced materials, including nanostructured catalysts, carbon-based Fe–N–C systems, metal–organic frameworks, and single-atom catalysts. Particular emphasis is placed on key performance parameters such as catalytic activity, manufacturability, stability, and catalyst lifespan. A critical comparison of these systems highlights the trade-offs between activity, cost, and scalability, demonstrating that the most advanced catalysts do not necessarily offer the best practical performance. A dedicated life cycle assessment perspective is included, focusing on catalyst lifespan, reuse efficiency, and iron leaching, providing quantitative insights into long-term sus-tainability. The analysis reveals that while advanced catalysts significantly improve cu-mulative catalytic output, their environmental and economic viability depends on synthe-sis complexity and durability under realistic conditions. Finally, current challenges and future directions are discussed, including the need for scalable synthesis methods, improved mechanistic understanding, and integration into hybrid treatment systems. This review aims to bridge the gap between fundamental re-search and practical application, offering guidance for the design of next-generation sus-tainable Fenton catalysts for wastewater treatment.

Abstract:

The viscosity stability of the polymer solution is one of the challenges in enhancing oil recovery and zwitterionic copolymer presents excellent viscosity stability and emulsification performance, enabling effective control the oil/water interface mobility and enhancing oil recovery. Herein, a zwitterionic copolymer (P(AM/AMBS/MAPTAC)) containing sulfonic acid group and quaternary amine group was synthesized by segmentation initiation with AM, AMBS and MAPTAC as monomers. The chemical structure of P(AM/AMBS/MAPTAC) was confirmed by FTIR and ¹H NMR. The M_w value of (P(AM/AMBS/MAPTAC)) was 9.91×10⁶, and the apparent viscosity of the solution of 2000 mg/L solution was 24.92 mP·s at 60 ℃ in the 5000 mg/L salt solution. P(AM/AMBS/MAPTAC) with the sulfonic acid group and the quaternary amine group exhibits outstanding salt tolerance and shear resistance. When the salinity was 10000 mg/L and the shear rate was 300 s^-1, the apparent viscosity and the viscosity reduction rates for the P(AM/AMBS/MAPTAC) solution were 23.45 mP·s and 69.23 %, respectively. Moreover, P(AM/AMBS/MAPTAC) exhibited higher emulsion property and higher oil-water interface thickness than HPAM and SPAM because of the synergistic effect of sulfonic acid and quaternary amine groups in the P(AM/AMBS/MAPTAC) molecule. The polymer flooding and the alkali-surfactant-polymer flooding formed by P(AM/AMBS/MAPTAC) had high chemical oil recovery and the oil displacement efficiency was higher than HPAM and SPAM in the polymer flooding and the alkali-surfactant-polymer flooding systems.

Abstract: The therapeutic monoclonal antibody bevacizumab is typically purified using Protein-A affinity chromatography, a highly effective but costly method. As a lower-cost alternative, affinity-based precipitation has been described to purify antibodies. Therefore, in this work, a precipitation protocol was developed for bevacizumab purification using the branched peptide (Ac-PHQGQHIG-Ahx₃)2-K-Ahx₃-PHQGQHIG-NH₂, which contains the epitope PHQGQHIG responsible for interaction with bevacizumab. The peptide was synthesised by microwave-assisted solid-phase peptide synthesis employing LiCl as an additive to prevent aggregation and ensure high purity and yield. Three molecules of 6-aminohexanoic acid were introduced between each epitope branch as spacer arms to promote the formation of cyclic complexes. Bevacizumab purification from the cell-free culture broth was achieved through a fractional precipitation process. First, a negative precipitation step using (NH₄)₂SO₄ 1.18 M was performed to remove contaminants. Afterwards, 5 moles of peptide per mol of bevacizumab were added to the supernatant, together with additional (NH₄)₂SO₄ to reach a final concentration of 1.20 M. Under these conditions, bevacizumab was recovered in the precipitate with 98% purity and a yield of 73%. In addition to being recyclable, the peptide´s relative low production cost may enable the development of a single-use purification process, which would be particularly advantageous for biopharmaceutical manufacturing.

Abstract: Background/Objectives: Microbial resistance to antibiotics has become a major global public health problem, threatening the effectiveness of current therapeutic strategies. The present study seeks to investigate natural compounds originating from fungal sources for their ability to interfere with efflux pump–mediated resistance in multidrug-resistant (MDR) bacteria, with the overarching goal of uncovering new candidates for antimicrobial therapeutic development. A chemical investigation of the ethanol extract of Termitomyces clypeatus was carried out to isolate and identify its constituents. Methods: Structural elucidation of the isolated metabolites was achieved through 1D and 2D NMR spectroscopy supported by mass spectrometric data. The crude extract and the purified compounds were then evaluated for their antibacterial activities individually, in the presence of an efflux pump inhibitor, and in combination with three antibiotics, using standardized microdilution assays. Results: Chromatographic separation of the extract yielded eleven known compounds including three sphingolipids: (9Z,12Z)-N-(1,3,4-trihydroxyoctadecan-2-yl)octadeca-9,12-dienamide (1), 2-hydroxy-N-(1,3,4-trihydroxyoctadecan-2-yl)hexadecanamide (2), and cerebroside B (3); four steroids: ergosterol (4), cerevisterol (5), ergosterol peroxide (6), and 5α,6α-epoxy-(22E,24R)-ergosta-8(14),22-diene-3β,7α-diol (7); one alkaloid: piperine (8); one carbohydrate: D-mannitol (9); and two phthalates: dimethyl phthalate (10) and bis(2-ethylhexyl) terephthalate (11). GC–MS analysis led to the identification of eight fatty acid derivatives (12–19). Sub-fraction A, along with compounds 3, 4, and 8 exhibited notable antibacterial activity against some tested strains with MIC values of 64 μg/mL. These compounds were identified as substrates of bacterial efflux pumps, and their presence enhanced the antibacterial effects of ciprofloxacin, doxycycline, and amikacin. Conclusion: The findings of the present work indicate that Termitomyces clypeatus contains antibacterial compounds with potential therapeutic value, both as standalone agents and as adjuvants that enhance the activity of conventional antibiotics.