Search Results (545)

The wine ecosystem constitutes a highly selective ecological niche characterized by low pH, high ethanol levels, sulfur dioxide, polyphenols, and nutrient limitation. During malolactic fermentation, this environment becomes dominated by specialized lactic acid bacteria (LAB), particularly Lactiplantibacillus plantarum and Oenococcus oeni, whose persistence under such stressors suggests the presence of adaptive traits relevant to probiotic development. In this study, twenty-three LAB isolates obtained from the spontaneous wine ecosystem were systematically evaluated through a multi-stage screening strategy. Primary single-factor assays revealed pronounced inter- and intraspecies variability in tolerance to acid, lysozyme, and bile salts. As a result, all O. oeni isolates and eight L. plantarum strains were excluded from further consideration. The four selected L. plantarum isolates (M-1, SY-2, XJA2, and XJ14) were subsequently subjected to simulated gastrointestinal challenges. Strains M-1 and XJ14 maintained high viability across both gastric and intestinal phases. In contrast, SY-2 and XJA2 exhibited pronounced gastric sensitivity but demonstrated strong survival in the intestinal phase. Functional characterization further distinguished the isolates: M-1 and XJ14 displayed balanced probiotic profiles, whereas XJA2 exhibited exceptional auto-aggregation and efficient metabolic capacity, suggesting specific colonization potential despite its gastric vulnerability. Comprehensive safety assessments confirmed the absence of hemolytic activity, biogenic amine production, and acquired antibiotic resistance in the tested isolates. Collectively, these findings identify M-1 and XJ14 as promising candidates for direct probiotic application, and XJA2 as a promising functional strain for encapsulation-based delivery. This study highlights the wine ecosystem as a valuable reservoir for novel probiotic development. Full article

N,N-Dimethyl-1,3-propanediamine (DMAPA) is an important aliphatic diamine widely used in fine chemical manufacturing. Its industrial production traditionally relies on Raney nickel catalysts, which suffer from pyrophoric hazards and limited selectivity due to imine condensation side reactions. To address these challenges, we report an Al₂O₃-supported Ni-Cu alloy catalyst as an efficient alternative for the selective hydrogenation of N,N-dimethylaminopropionitrile (DMAPN). The optimized Ni₃₀Cu₅/Al₂O₃ catalyst achieves complete DMAPN conversion and over 90% DMAPA selectivity under industrially relevant conditions (120 °C, 2.5 MPa H₂). X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analyses confirm the formation of substitutional Ni-Cu alloy nanoparticles, where Cu incorporation induces both geometric isolation of Ni ensembles and electronic modulation of surface active sites, thereby suppressing condensation-derived by-products. In addition, an NH₃/ethanol-assisted process further improves selectivity while reducing autogenous operating pressure. Overall, this work demonstrates a safe and highly selective catalytic system for primary diamine synthesis, providing a practical alternative to conventional Raney Ni-based processes. Full article

Predicting CO₂ absorption behavior in aqueous amine systems is a critical challenge for optimizing carbon capture technologies. This research develops a high-precision Artificial Neural Network (ANN) to simulate equilibrium data across various amine classes, including primary (MEA, DGA), secondary (DEA, DPA), and tertiary (MDEA) amines. The model architecture utilizes a Multi-Layer Perceptron (MLP) trained on a dataset split into 70% training, 15% validation, and 15% testing segments to prevent overfitting and ensure reliable generalization. By employing a Sigmoid activation function, the network achieved a coefficient of determination (R²) exceeding 0.98 and an absolute average relative deviation (AARD) below 5%. Furthermore, this study evaluates the efficacy of classical isotherms (Langmuir, Freundlich, and Temkin) strictly as empirical curve-fitting correlations for liquid-phase behavior. Results indicate that while these models are traditionally surface-adsorption based, the Langmuir form provides a mathematically robust fit for the tertiary amine MDEA (R² = 0.9673). Experimental observations indicate that Monoethanolamine (MEA) maintains the highest capacity for CO₂ uptake. Since the model relies on categorical descriptors for amine types, it offers a rapid and efficient framework for assessing specific solvents in post-combustion capture infrastructure. Full article

This study investigates the protective performance of a triazole-based Mannich base corrosion inhibitor, 4-((1,2,4-triazolyl)methyl) dibutylamine (TZMBA), on P110 carbon steel in dissolved oxygen environments. TZMBA was synthesized via a Mannich reaction, and its molecular structure was confirmed by Fourier transform infrared spectroscopy (FT-IR). The corrosion inhibition behavior and underlying mechanisms were systematically explored through weight loss measurements, surface characterization, and multiscale molecular simulations. Weight loss results indicated that TZMBA significantly mitigates the corrosion of P110 steel, with inhibition efficiency reaching 81.5% at 1.67 mmol/L and 82.0% at 2.14 mmol/L. Adsorption thermodynamic analysis revealed that the process follows the Langmuir isotherm model. The calculated standard Gibbs free energy ${∆G}_{ads}^0$ of −38.69 kJ/mol suggests a spontaneous, mixed-type adsorption mechanism involving both physisorption and chemisorption. Scanning electron microscopy (SEM) observations confirmed a marked reduction in surface degradation, characterized by suppressed corrosion products and minimized localized attack. X-ray photoelectron spectroscopy (XPS) further verified that TZMBA anchors to the metal surface through chemical coordination, forming a robust organic-inorganic composite film. From a theoretical perspective, frontier molecular orbital (FMO) analysis showed that TZMBA’s high E_HOMO and narrow energy gap facilitate efficient electron transfer. Combined Fukui function and molecular electrostatic potential (MEP) maps identified the nitrogen atoms in the triazole ring and amine group as the primary active sites. Furthermore, molecular dynamics (MD) simulations demonstrated that TZMBA molecules adopt a nearly parallel configuration on the Fe surface. The high negative interaction energy obtained from MD simulations confirms a strong binding affinity and a potent inherent driving force for the formation of a stable protective layer. Overall, the integration of experimental data and theoretical calculations establishes TZMBA as an effective inhibitor that provides superior protection by forming a stable, compact adsorption film on P110 carbon steel. Full article

Long-term soil fertility is governed by the metabolic plasticity of microbial communities, particularly during the decomposition of crop residues. This study investigated the straw-associated functional microbial profile associated with straw decomposition under the influence of 62 years of continuous management with mineral fertilization and liming. Using the Biolog EcoPlateTM approach combined with a modified litter-bag protocol, we assessed shifts in metabolic activity patterns of functional guilds and groups. PERMANOVA results revealed that the interaction between liming and fertilization (p < 0.05) was the primary driver of divergence in functional communities, rather than the individual effect of factors. Long-term treatments induced a significant reconfiguration of the functional niche, shifting from the native, generalist microbiome to specialized communities in treated variants, with carbohydrate (CH) guilds as dominant and indicators of community performance. Moderate levels of liming (L1) stimulated metabolic activity and maintained higher functional diversity across amino acid (AA) and polymers (Px) guilds. Intensive liming (L2), in contrast, restricted the activity of most microbial functional groups and favored amine (AM) and carboxylic acid (CX) guilds. Shifts from a generalist microbiome in native soil to specialized communities in treated soils show the capacity of microorganisms to adapt efficiently under agronomic management. Full article

Micro- and nanoplastics represent ubiquitous environmental contaminants with emerging concerns regarding their impact on human health. The gastrointestinal tract is the primary site of contact, where micro- and nanoplastics may interact with the intestinal epithelium, potentially disrupting barrier integrity, altering microbiota composition, and triggering inflammatory or oxidative stress responses. Moreover, variability in particle size, shape, chemical composition, and surface modifications adds complexity to assessing their health impact. Findings remain inconsistent, and the mechanisms of toxicity are not yet fully elucidated. This study developed a tri-culture in vitro intestinal barrier model incorporating Caco-2 enterocytes, HT29-MTX mucus-secreting cells, and Raji B-induced M-like cells to mimic the structural and functional features of the human gut epithelium. Polystyrene beads of different sizes (40 nm and 200 nm) and surface functionalization (carboxylated and aminated) were characterized and exposed to the model to examine their effects on barrier integrity, cellular uptake, and cytotoxicity. The results showed that size and surface chemistry play key roles in particle interaction dynamics with the intestinal barrier, affecting cellular internalization and toxicological outcomes. This validated in vitro model provides a valuable tool for investigating micro- and nanoplastic behavior upon oral exposure, contributing to more accurate health risk assessments associated with plastic pollution. Full article

In this study, a comprehensive derivatization strategy for biogenic amines based on the formation of volatile carbamate derivatives using 2,2,2-trifluoroethyl chloroformate (TFECF) was successfully developed and evaluated. A series of biogenic amine derivatives was obtained in excellent yields (94–99%) and structurally confirmed using NMR, MS, and crystal structure analysis. The reagent demonstrated high reactivity toward primary and secondary amines, providing derivatives of excellent purity and satisfactory volatility. The applicability of the proposed procedure to real food matrices was demonstrated using GC-MS. The obtained results were compared with the corresponding ethyl chloroformate (ECF) derivatives. TFECF derivatives exhibited significantly improved volatility, reflected in shorter retention times and enhanced analytical performance. Full article

Biosurfactants produced by halophilic bacteria are gaining attention as eco-friendly and biocompatible alternatives to synthetic surfactants due to their high surface activity, stability under extreme conditions, and intrinsic antimicrobial properties. These amphiphilic biomolecules hold great promise for bioremediation, biomedical, and pharmaceutical applications. In this study, moderately halophilic bacteria capable of biosurfactant production were isolated from saline mud collected at the Burgas solar salterns (Bulgaria). The halophilic microbiota was enriched in Bushnell–Haas (BH) medium containing 10% NaCl amended with different carbon sources. Primary screening in BH liquid medium evaluated the isolates’ ability to degrade n-hexadecane while at the same time producing biosurfactants. Thirty halophilic bacterial strains were isolated on BH agar plates supplemented with 2% n-hexadecane, 2% olive oil, or 2% glycerol. Four isolates—BS7OL, BS8OL, BS9GL, and BS10HD—with strong emulsifying activity (E₂₄ = 56%) and reduced surface tension in the range of 27.3–45 mN/m were derived after 7 days of batch fermentation. Strain BS10HD was chosen as the most potent biosurfactant producer. Its phylogenetic affiliation was determined by 16S rRNA gene sequence analysis; according to the nucleotide sequence, it was assigned to Halomonas ventosae. The extract material was analysed by thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR). Upon spraying the TLC plate with ninhydrin reagent, the appearance of a pink spot indicated the presence of amine functional groups. FTIR analysis showed characteristic peaks for both lipid and peptide functional groups. Based on the observed physicochemical properties and analytical data, it can be suggested that the biosurfactant produced by Halomonas ventosae BS10HD is a lipopeptide compound. Full article

Although technologies used in non-fossil methane and fossil resources to produce blue hydrogen are relatively mature, a system-integrated approach to reference system (RS)-based purification of H₂, CO₂ capture and storage, and UHS is relatively unexplored and requires research to fill gaps in the literature regarding balanced permutations and geological viability for net-zero requirements. This research proposes a system-integrated process for H₂ production through a PSA-based purification technique coupled with amine-based CO₂ capture and underground hydrogen storage (UHS). The intellectual novelty of the research is its first quantitative treatment of synergistic effects such as heat recovery and pressure-matching across units. Additionally, a site separation technique is applied, where H₂ and CO₂ reservoirs are selected based on the permeability of rock formations and fluids. On a research methodology front, a base case of a steam methane reforming process with the production of 99.99% pure H₂ at a production rate of 5932 kg/h is modeled and simulated using Aspen Plus™ to create a balanced permutation of mass and energy across units. As per the CO₂ capture requirements of this research, a capture of 90% of CO₂ is accomplished from the production of 755 t/d CO₂ within the model. The compressed CO₂ is permanently stored at specifically identified rock strata separated from storage reservoirs of H₂ to avoid empirically identified hazards of rock–fluid interaction at high temperatures and pressures. The lean amine cooling of CO₂ to 60 °C and elimination of tail-gas recompression simultaneously provides 5.4 MW_th of recovered heat. The integrated design achieves a net primary energy penalty of 18% of hydrogen’s LHV, down from ~25% in a standalone configuration. This corresponds to an energy saving of 8–12 MW, or approximately 15–18% of the primary energy demand. The research computes a production cost of H₂ of 0.98 USD per kg of H₂ within a production atmosphere of a commercialized WGS and non-fossil methane-based production of H₂. Additionally, a sensitivity analysis of ±23% of the energy requirements of the reference system shows no marked sensitivity within a production atmosphere of a commercially available WGS process. Full article

To address the issues of slow curing rate, post-curing reactions, and suboptimal mechanical properties in the carboxyl-terminated polybutadiene (CTPB)/epoxy resin (EP) binder system used for solid propellants, this study optimized the curing system by introducing 593 aliphatic amine compounds containing primary and secondary amine groups as a cure accelerator. It is found that the incorporation of the cure accelerator improved the fracture strength and elongation at break of the CTPB/EP binder system. With the addition of 0.3 wt.% cure accelerator, the tensile fracture strength increased to 0.37 MPa, while the elongation at break reached 655%. Moreover, augmenting the quantity of cure accelerator can substantially elevate the crosslink density and gel fraction of the binder system. When the addition reaches 0.3 wt.%, the crosslink density is 4.3 × 10⁻⁴ mol/cm³. Further studies showed that 593 cure accelerator reduced the activation energy of the curing reaction of the CTPB/EP binder system, with higher levels of cure accelerator resulting in lower activation energy. This study established a preparation methodology for a CTPB/EP binder system with high elongation and tensile strength. These findings provide a solid scientific foundation for the application of CTPB-based binder systems in solid propellants. Full article

Nucleophilic ring-opening of bis(oxiranes), containing several reactive centers, can be used to elaborate straightforward atom-economy and stereoselective approaches to polyfunctionalized compounds. In the present work, ring-opening of cis- and trans-diastereomers of a spirocyclic bis(oxirane), containing a cyclooctane core (namely, 1,8-dioxadispiro[2.3.2.3]dodecane), upon treatment with various amines, was studied. Trans-isomer afforded aminoalcohols with 9-oxabicyclo[3.3.1]nonane moiety, formed via domino-process, including opening of an oxirane ring followed by intramolecular cyclization. Ring-opening of cis-isomer gave aminosubstituted cis-cyclooctane-1,5-diols, derived from independent reaction of two oxirane moieties. Activation of oxirane rings by the addition of LiClO₄, acting as a Lewis acid, allowed the involvement of a number of primary and secondary aliphatic amines as well as aniline derivatives in the reaction. Scope and limitations of the reaction were studied and a series of aminoalcohols with a 9-oxabicyclo[3.3.1]nonane core and symmetric diaminodiols with a cyclooctane core were obtained. Full article

Fermented meat products rely on complex microbial ecosystems in which lactic acid bacteria (LAB) play a central role in safety, quality, and sensory development. In recent years, increasing demand for reduced-nitrite formulations, clean-label products, and improved risk management have driven renewed interest in microbial control strategies beyond traditional fermentation practices. This systematic review aims to synthesize current knowledge on the microbiological aspects of meat fermentation, spanning traditional spontaneous processes and modern approaches to microflora control, including starter cultures, biocontrol strategies, and omics-based tools. A systematic literature search was conducted in PubMed, Web of Science, Scopus, and Google Scholar, with the final search performed on 15 May 2025. After screening and eligibility assessment following PRISMA 2020 guidelines, 141 studies were included in the qualitative synthesis. The review integrates evidence on microbial succession, metabolic functions, pathogen inhibition, biogenic amine control, and flavour formation, with particular emphasis on advances in metagenomics, metabolomics, and predictive microbiology. Across studies, LAB-dominated ecosystems—particularly those involving Latilactobacillus sakei, Latilactobacillus curvatus, and Lactiplantibacillus plantarum—consistently emerge as the primary drivers of fermentation stability and safety. The strongest evidence supports the use of selected starter and protective cultures, bacteriocinogenic LAB, and omics-guided predictive control to enhance process reliability, support reduced-nitrite strategies, and mitigate microbiological risks without compromising product quality. Overall, the integration of traditional fermentation knowledge with data-driven microbial management provides a robust framework for developing safe, authentic, and sustainable fermented meat products. Full article

This study systematically investigates the catalytic effect of histidine (HIS) on CO₂ desorption in amine-based solvents, with a primary focus on 30 wt% N-(2-aminoethylamino)ethanol (AEEA) and its blends with N-methyldiethanolamine (MDEA). Experimental results show that the addition of 0.22 wt% HIS significantly enhances both the equilibrium desorption amount and the maximum desorption rate of CO₂, particularly at elevated temperatures (e.g., 100 °C). Under optimal conditions, HIS increased the maximum desorption rate by 22.1% and reduced the heat duty to 71.7% compared to the non-catalytic benchmark. The catalytic performance was further confirmed in AEEA-MDEA mixed solvents, with the most pronounced effect observed in the 3:2 molar ratio system, where HIS enhanced both the equilibrium desorption amount and the maximum desorption rate by 15.3% and 20.8%, respectively. Through ¹³C NMR analysis and pH-dependent speciation monitoring, we revealed that HIS alters the reaction pathway by suppressing the formation of stable carbamate species (AEEA_(a)COO⁻). The protonated (HIS⁺) and neutral (HIS^±) forms were identified as the active species that promote more direct CO₂ release from carbamate, while the deprotonated (HIS⁻) form facilitates proton transfer and amine regeneration. HIS also exhibited excellent catalytic stability over 10 absorption–desorption cycles. These findings highlight HIS as an efficient and stable organocatalyst for energy-efficient CO₂ desorption processes. Full article

Methenamine, a urinary antiseptic with antimicrobial properties, decomposes into toxic formaldehyde under acidic conditions. Its use is prohibited in dairy cattle in Korea to prevent harmful residues in milk. This study was designed to develop and validate a sensitive and reliable LC–MS/MS method for determining methenamine in raw milk and bovine muscle in compliance with the Positive List System (PLS) regulations. Samples were extracted with acetonitrile (ACN)–methanol (MeOH) (7:3, v/v) containing ammonia water, followed by defatting with n-hexane and purification with primary secondary amine (PSA). Chromatographic separation was performed on a hydrophilic interaction liquid chromatography (HILIC) column, and quantification was conducted using matrix-matched calibration to minimize matrix effects. The method showed excellent linearity (R² > 0.999), low limits of quantification (LOQ) (0.49 μg/kg for raw milk; 0.64 μg/kg for bovine muscle), and acceptable recoveries (78.1–102.8%) with precision (CV ≤ 8.75%), meeting Codex CAC/GL 71-2009 criteria. Stability studies demonstrated that methenamine remained stable in stock solutions, working standards and processed extracts under the storage and handling conditions used. Application to incurred samples resulted in the detection of methenamine in 2 of 32 raw milk samples (0.65 and 1.14 μg/kg) but in none of the 25 bovine muscle samples, with all detected levels below the Korean PLS limit. These findings confirm that the developed method is accurate, sensitive, and applicable for routine surveillance of methenamine residues to ensure consumer safety. Full article

The presence of vanadium compounds in heavy oils poses a significant challenge by poisoning and deactivating refining catalysts, making their removal an essential processing step. However, this process is challenged by the competitive adsorption of abundant polycyclic aromatic hydrocarbons (PAHs) in heavy oils, due to the similar conjugated π-electron structure of PAHs and vanadyl porphyrins. In the presented study, the adsorption behaviors of vanadyl octaethylporphyrin (VOOEP) and 1-methylpyrene (1-MP) on various solid adsorbents were investigated. Among the adsorbents studied, the primary secondary amine adsorbent (PSA) demonstrated superior performance, achieving high VOOEP adsorption capacity and exceptional selectivity, even in the presence of a large excess of 1-MP. The adsorption kinetics, isotherms, and thermodynamics of VOOEP and 1-MP onto PSA were studied. Four common kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion) were used for data fitting. The adsorption isotherms were modeled using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms. The adsorption kinetics for both VOOEP and 1-MP on PSA were best described by the pseudo-second-order model, while equilibrium data were well fitted by the Freundlich isotherm. Thermodynamic analysis confirmed that the adsorption of VOOEP and 1-MP on PSA is a spontaneous and exothermic process. The practical applicability of PSA was confirmed with a heavy deasphalted oil (HDAO), where it efficiently removed vanadium with high selectivity, with lower co-adsorption of desirable oil components. The results indicate that PSA is a promising adsorbent for effectively removing vanadium compounds from heavy oils. Full article