Search Results (227)

Lactic acid is a compound that is consistently in high demand due to its wide range of applications. Aiming at the use of an alternative third-generation substrate for the microbial production of this organic acid, the fermentation of Porphyra umbilicalis with lactobacilli was studied. This seaweed revealed a total carbohydrate content of 51.6 ± 1.7 g/100 g biomass dry weight (DW), thus showing great potential for fermentation purposes. Thermal-acidic (at 121 °C for 30 min) hydrolysis of 100 g/L P. umbilicalis with sulfuric acid (H₂SO₄ 5% w/v) led to the release of 37.9 ± 1.1% of the total sugars in the seaweed substrate, producing a hydrolysate with 14.7 ± 0.4, 1.1 ± 0.04 and 0.9 ± 0.04 g/L of galactose, glucose and 5-hydroxymethylfurfural (HMF), respectively. After optimization of the oxygen supply conditions, fed-batch fermentation of the hydrolysate by a consortium (4LAB) of Levilactobacillus brevis, Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and Lacticaseibacillus casei in a 2 L bioreactor produced up to 65 g/L of lactic acid with a yield of 0.58 g/g of consumed carbon sources. The 4LAB consortium was not inhibited by up to 1 g/L HMF in the medium and also showed the capacity to convert up to 88.5% of the initial HMF titer during fed-batch fermentation in the bioreactor. Full article

Barley wine is one of the most chemically complex and historically significant beer styles, yet its molecular composition remains largely unknown. This study aims to create the first detailed molecular framework for understanding the chemical diversity of barley wine and cereal wines. The chemical diversity of barley wines and related “cereal wines” made from wheat, oats, and rye, including barrel-aged varieties, is examined using ¹H nuclear magnetic resonance (NMR) metabolomics. Distinct cereal-dependent signatures were revealed by multivariate analyses. High levels of fusel alcohols and phenolic acids were present in barley wines. Elevated levels of pyruvate and aromatic amino acids were found in wheat wines, and high levels of maltodextrin, arabinose, and trigonelline were found in oat and rye wines. A comparison of sub-styles showed that English and American barley wines were different based on ester and complex sugar profiles. Barrel aging introduces changes dependent on the barrel’s origin. A reliable classification of barrel origin was allowed for by a decision tree with four diagnostic metabolites—5-hydroxymethylfurfural (HMF), acetaldehyde, mannose, and tryptophan. The way in which raw materials, fermentation conditions, and the reuse of barrels collectively influence their metabolomes is exemplified. Verifying the authenticity of beer, evaluating its quality, and generating new ideas for high gravity brewing are all cases in point for this approach. Full article

The Small Punch Test (SPT) has been developed as a small sample technique for the evaluation of mechanical properties of structural materials. However, the SPT is subject to systematic biases, resulting in inaccurate estimates of Uniaxial Tensile Test (UTT) properties. In this study, an experimental approach has been adopted to investigate the potential of neural networks to predict UTT-equivalent behavior from SPT measurements. An experimental database containing paired SPT and UTT data has been prepared for three boiler steels (10H2M, 13HMF, and 15HM) in both new and service-degraded states. Convolutional neural networks (CNN) have been trained and evaluated for curve-to-curve prediction. The working hypothesis is that CNN models, by exploiting local curve features, are capable of reducing the systematic bias inherent to SPT, generating estimates of UTT properties with precision comparable to conventional UTT measurements. Consistent with trends in applied deep learning, the results confirm the robustness of convolutional architectures. In general, the findings provide strong evidence that CNNs can translate SPT data into UTT equivalent material properties, thereby bridging a long-standing methodological gap and supporting automated evaluation of structural steels in service. Full article

The application of water-tolerant bifunctional solid acids with high kinetic performance in converting glucose to 5-hydroxymethylfurfural (HMF) presents a number of challenges. In this study, the effect of doping a hierarchically porous tantalum phosphate monolith with transition metal ions (Nb⁵⁺, V⁵⁺, Zr⁴⁺, Ni²⁺, and Zn²⁺) was explored in delivering superior glucose dehydration kinetics and stability. Doping with Nb⁵⁺ (x%Nb-TaP) resulted in the best catalytic performance with enhanced tantalum phosphate stability. The incorporation of Nb⁵⁺ ions inhibited tantalum phosphate crystallization, increased the density of Lewis acid and Brønsted acid sites and average mesopore size, with consequently enhanced kinetics, enabling the reaction kinetics of fructose to approach a steady state. Application of a 25% mol/mol Nb (25%Nb-TaP) activated at 600 °C to convert 1.0 wt.% glucose in a water/methyl isobutyl ketone (MIBK) biphasic system delivered an HMF yield and selectivity of 72.6% and 95.6%, respectively. Moreover, an HMF productivity of 0.11 mol·h⁻¹·kg-solution⁻¹ was achieved by treating a 15.0 wt.% glucose feed at 170 °C in a water/MIBK biphasic system at a catalyst loading of 10.0 wt.%. The 25%Nb-TaP catalyst largely retained its initial activity after three recycles in the water/MIBK biphasic system, generating an HMF yield of 54.1% and selectivity of 87.0%. The results of this study demonstrate the significant potential of Nb-TaP for industrial-scale HMF production. Full article

2,5-furandicarboxylic acid (FDCA), a high-value biomass-derived monomer, serves as a crucial building block for sustainable polymers including polyesters, polyamides, and polyurethanes. This study systematically investigated the catalytic oxidation of 5-hydroxymethylfurfural (HMF) to FDCA over Pt/Al₂O₃ and Pt–Bi/Al₂O₃ catalysts. The 5Pt/Al₂O₃ catalyst yielded 60.6% FDCA after 12 h under optimized conditions (80 °C, 0.1 MPa O₂, 1 equiv. Na₂CO₃). Remarkably, Bi-modified 5Pt–1Bi/Al₂O₃ catalyst dramatically enhanced catalytic performance, achieving 94.1% FDCA yield within 6 h under optimized conditions (80 °C, 1.5 MPa O₂, 2 equiv. Na₂CO₃). Comprehensive characterization revealed that the exceptional activity originates from Bi–O–Pt interactions that modulate the electronic structure and oxidation state of Pt active sites, which facilitates the oxidation of intermediate 5-formyl-2-furancarboxylic acid (FFCA) to FDCA, the rate-limiting step of HMF oxidation. This work demonstrates an efficient Bi-promoted Pt catalytic system for FDCA production with significant potential for industrial application. Full article

5-hydroxymethylfurfural (5-HMF) has been shown to exert neuroprotective effects in a global cerebral ischemia mouse model in our previous study, where it demonstrated antioxidant and anti-inflammatory properties. However, studies on its antidepressant mechanisms remain scarce. Since oxidative stress and neuroinflammation are closely associated with depression, this study investigated the antidepressant effects of 5-HMF, focusing on its potential inhibition of oxidative stress via the Nrf2 pathway and its role in microglial M1 polarization-mediated neuroinflammation. An acute depression mouse model induced by intraperitoneal injection of lipopolysaccharide (LPS) was utilized. Mice received 5-HMF (12 mg/kg) or an equal volume of vehicle via intraperitoneal injection 30 min prior to and 5 min after LPS administration. At 24 h post-modeling, behavioral tests (sucrose preference, forced swim, and open field tests) were conducted to evaluate the antidepressant effect of 5-HMF. Histological damage in the hypothalamus was assessed using Nissl staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. Immunofluorescence was performed to evaluate M1 polarization of hypothalamic microglia. Oxidative stress damage was assessed by measuring malondialdehyde (MDA), carbonyl groups, and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels. Nrf2 DNA-binding activity was examined using an ELISA-based assay. The expression of inflammatory cytokines, Nrf2, and downstream antioxidant proteins was analyzed by ELISA kits and Western blotting. 5-HMF significantly alleviated LPS-induced depression-like behaviors, reduced hypothalamic neuronal damage, decreased oxidative stress, and inhibited microglial M1 polarization. It also regulated the expression of inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-4, and IL-10) and activated the Nrf2 signaling pathway, enhancing nuclear translocation efficiency. Notably, these effects were significantly attenuated by the Nrf2 inhibitor brusatol. In conclusion, 5-HMF exerts neuroprotective effects by modulating Nrf2-mediated oxidative stress responses and suppressing microglial M1 polarization-driven neuroinflammation. These findings suggest that 5-HMF may provide therapeutic potential for alleviating depression symptoms induced by acute inflammation. Full article

Biocatalysis is fundamental to biological processes and sustainable chemical productions. Over time, the biocatalysis strategy has been widely researched. Initially, biomanufacturing and catalysis of high-value chemicals were carried out through direct immobilization and application of biocatalysts, including natural enzymes and living cells. With the evolution of green chemistry and environmental concern, hybrid photoelectro-biocatalysis (HPEB) platforms are seen as a new approach to enhance biocatalysis. This strategy greatly expands the domain of natural biocatalysis, especially for bio-based components. The selective valorization of renewable furan derivatives, such as 5-hydroxymethylfurfural (HMF) and furfural, is central to advancing biomass-based chemical production. Biocatalysis offers high chemo-, regio-, and stereo-selectivity under mild conditions compared with traditional chemical catalysis, yet it is often constrained by the costly and inefficient regeneration of redox cofactors like NAD(P)H. Photoelectrocatalysis provides a sustainable means to supply reducing equivalents using solar or electrical energy. In recent years, hybrid systems that integrate biocatalysis with photoelectrocatalysis have emerged as a promising strategy to overcome this limitation. This review focuses on recent advances in such systems, where photoelectrochemical platforms enable in situ cofactor regeneration to drive enzymatic transformations of furan-based substrates. We critically analyze representative coupling strategies, materials and device configurations, and reaction engineering approaches. Finally, we outline future directions for developing efficient, robust, and industrially viable hybrid catalytic platforms for green biomass valorization. Full article

The Earth’s geomagnetic field (GMF) is a fundamental environmental signal for plants, with its perception rooted in quantum biology. Specifically, the radical pair mechanism (RPM) explains how this weak force influences electron spin states in metabolic pathways, providing a framework for its profound biological impact. Research shows that a hypomagnetic field (hMF) directly reduces the production of reactive oxygen species (ROS), creating a quantum signature in plants. This is a counterintuitive finding, as it suggests the plant perceives less oxidative stress and, in response, downregulates its antioxidant defenses. This multi-level effect, from a quantum trigger to molecular and metabolic changes, ultimately affects the plant’s growth and phenotype. This review suggests a possible link between the GMF and plant health, identifying the GMF as a potential physiological modulator. Manipulating the magnetic field could therefore be a novel strategy for improving crop resilience and growth. However, the fact that some effects cannot be fully explained by the RPM suggests other quantum mechanisms are involved, paving the way for future research into these undiscovered processes and their potential inheritance across generations. Full article

Furfural and 5-hydroxymethylfurfural are considered as essential platform molecules for the chemical industry, acting as precursors and intermediates of numerous products. They are produced from pentoses and hexoses, respectively, in an acid medium. In this work, biomass from a green macroalgae, Ulva rigida, was treated under acidic conditions provided by heterogeneous catalysts in order to promote the dehydration of its monosaccharides into furfural and 5-hydroxymethylfurfural. Particularly, two functionalized mesoporous silicas, HMS and SBA-supported metal oxides (Nb₂O₅ and ZrO₂), were used as catalysts. Their textural, structural, and acid properties were deeply studied, providing excellent BET surface areas (ranging 424 to 1204 m²/g) and a high concentration of acid sites (220–460 µmol/g), which then translated into great catalytic performances (77.8% and 64.1% of furfural and HMF molar yields, respectively, using HMS-Nb) after a 4 h of reaction time at 180 and 160 °C, respectively. The catalyst showed excellent stability and recyclability as it could be reused for up to five reaction runs with only a slight decrease in performance. Full article

The dehydration of fructose and glucose to 5-hydroxymethylfurfural (HMF) in water solution was carried out in the presence of functionalized heteropolyanion-based heterogeneous catalysts. Two catalysts were prepared by immobilizing the Keggin polyoxometalate H₃PW₁₂O₄₀ (PW₁₂) onto nanoSiO₂ by the use of imidazoline and -SO₃⁻ surface species through acid–base reactions. The catalysts were characterized by N₂ adsorption–desorption isotherms, XRD, TGA, FTIR, solid-state NMR, SEM, and acidity–basicity measurements. Catalytic reactions in batch conditions were performed at 165 °C in the presence of suspended catalysts, and the yield of furfural and 5-hydroxymethylfurfural (5-HMF) was determined. The catalytic activity of the materials was tested for sugars at 1M concentration in a water solution. The valorization of sugars (fructose and glucose) was found to be more effective in the case of fructose. Furthermore, the two catalysts in which the heteropolyacid was immobilized showed activity similar to that observed for naked PW₁₂ (reaction in homogeneous phase), despite the heterogeneous nature of the process, but with the advantage of easier separation at the end of the reaction by simple filtration. The material’s substantial stability was demonstrated through three consecutive catalytic test cycles, in which the same catalyst was recovered after each experiment and washed several times with hot water. Finally, tests devoted to the valorization of sugars contained in wastewater from the brewing industry provided a poor yield in 5-HMF, indicating that the catalysts prepared here were, unfortunately, not suitable for this transformation under the conditions tested. This was because the catalysts prepared in this work showed a low capacity to transform glucose (the most present sugar in the carbohydrate fraction of this biomass) into furans. Full article

In porphyry systems, the physicochemical properties of ore-related intrusions critically influence both metallogenic fertility and the resulting metal assemblages. Biotite is a widespread magmatic mineral capable of recording subtle changes in physicochemical parameters throughout the evolution of porphyry systems. Throughout the years, several biotite thermobarometers have been proposed; however, the most appropriate combination for application to porphyry systems remains uncertain. In the Julong Cu–polymetallic district, where magmatic biotite is pervasive in the ore-related intrusive suite, we integrate available temperature, pressure, and oxygen fugacity data to assess which combination of biotite-based thermobarometers best captures the physicochemical condition of the magma. Our results demonstrate that the structural formula recalculation method of Li et al. (2020), when combined with the thermometer of Li and Zhang (2022) and the barometer of Uchida et al. (2007), yields the most accurate reconstruction of magmatic conditions in porphyry systems. In the Julong district, this integrated approach reveals that the earliest granodiorite crystallized at depths of ~3.2–6.3 km, under strongly oxidizing conditions (~NNO+3 to HM) and in the presence of elevated volatile concentrations. A slightly younger monzogranite formed at ~4.4 km depth, recording lower oxygen fugacity conditions (~NNO+2 to NNO+4). Its elevated F concentration and lower oxygen fugacity suggest a genetic link to the fractional crystallization of magmatic phases, especially magnetite. On the other hand, the ore-related monzogranite porphyry (~NNO+3 to HM) shares the oxidized signature of the granodiorite and was emplaced at ~3.4 km depth. Its low log(f_H2O/f_HCl) value reflects elevated HCl activity, conducive to the efficient magmatic transport of Cu and Mo. Full article

Introduction: 5-HMF is a molecule found in carbohydrate-rich foods that is associated not only with cancer and anaphylactic reactions, but also with anti-oxidant properties. Questions arose as to whether 5-HMF exhibited a catalytic effect in relation to lipid peroxidation and lipoprotein oxidation in presence of metals and/or radicals. Methods: Peroxynitrite (ONOO⁻)-induced chemiluminescence and ONOO⁻ nitration of tyrosine residues on BSA using anti-nitro-tyrosine-antibodies were used to measure the protection of 5-HMF against peroxides or nitration compared to vitamin C (VitC). The reductive potential of 5-HMF or VitC on Cu²⁺ or Fe³ was estimated using the bicinchoninic acid (BCA) or Fenton-complex method. Human plasma was used to measure the generation of malondialdehyde (MDA), 4-hydroxynonenal (HNE), and total thiols after Fe²⁺/H₂O₂ oxidation in the presence of different concentrations of 5-HMF or VitC. Finally, Cu²⁺ oxidation of LDL after 4 h was carried out with 5-HMF or VitC, measuring the concentration of MDA in LDL with the thiobarbituric assay (TBARS). Results: VitC was 4-fold more effective than 5-HMF in scavenging ONOO⁻ to nearly 91.5% at 4 mM, with the exception of 0.16 mM, where the reduction of ONOO⁻ by VitC was 3.3-fold weaker compared to 0.16 mM 5-HMF. VitC or 5-HMF at a concentration of 6 mM inhibited the nitration of tyrosine residues on BSA to nearly 90% with a similar course. While 5-HMF reduced free Fe³⁺ in presence of phenanthroline, forming Fe²⁺ (phenantroleine)₃ [Fe²⁺(phe)₃] or complexed Cu²⁺(BCA)₄ to Cu⁺(BCA)₄ weakly, VitC was 7- to 19-fold effective in doing so over all the used concentrations (0–25 mM). A Fe²⁺—H₂O₂ solution mixed with human plasma showed a 6–10 times higher optical density (OD) of MDA or HNE in the presence of 5-HMF compared to VitC. The level of thiols was significantly decreased in the presence of higher VitC levels (1 mM: 198.4 ± 7.7 µM; 2 mM: 160.0 ± 13.4 µM) compared to equal 5-HMF amounts (2562 ± 7.8 µM or 242.4 ± 2.5 µM), whereas the usage of lower levels at 0.25 µM 5-HMF resulted in a significant decrease in thiols (272.4 ± 4.0 µM) compared to VitC (312.3 ± 19.7 µM). Both VitC and 5-HMF accelerated copper-mediated oxidation of LDL equally: while the TBARS levels from 4 h oxidized LDL reached 137.7 ± 12.3 nmol/mg, it was 1.7-fold higher using 6 mM VitC (259.9 ± 10.4 nmol/mg) or 6 mM 5-HMF (239.3 ± 10.2 nmol/mg). Conclusions: 5-HMF appeared to have more pro-oxidative potential compared to VitC by causing lipid peroxidation as well as protein oxidation. Full article

With increasing concerns about climate change and the depletion of fossil fuels, hemicellulose sugars from lignocellulosic biomass are gaining attention as sustainable feedstocks for producing biofuels and valuable chemicals. In this study, the extraction of hemicellulose sugars from corncob biomass was performed using hydrothermal pretreatment. Response Surface Methodology (RSM) with the Box–Behnken Design (BBD) was employed to optimize different parameters. The tested parameters included the corncob-to-water ratio (0.5:10, 1.5:10), time (30 to 90 min), and temperature (150 to 170 °C), to achieve the highest sugar yields (xylose, arabinose, and total sugars). The ANOVA results for the full quadratic polynomial model, which evaluates the effects of the three variables on xylose yield, indicate that the model is highly significant and provides a good fit to the data. This was evidenced by the minimal difference (0.003) between the predicted R² and the adjusted R². This study reports one of the highest recoveries of hemicellulosic sugars from corncobs and also evaluates degradation byproducts, offering a more efficient and comprehensive pretreatment approach that employs a lower temperature and a mild acid concentration (1%) compared with earlier research. The highest yields of xylose (103.49 mg/g), arabinose (26.75 mg/g), and total sugars (163.21 mg/g) were obtained at 160 °C and a corncob-to-water ratio of 0.5:10, after 90 min. Degradation products such as HMF and furfural in the hydrolysate were also analyzed by HPLC. The hydrolysate obtained from hydrothermal pretreatment contained oligomers that were converted into monomers through 1% H₂SO₄ hydrolysis. The highest yields after the acidic hydrolysis were 301.93 mg/g xylose, 46.96 mg/g arabinose, and 433.79 mg/g total sugars hydrolysis. Full article

Aiming to address the key challenges of poor enzyme stability, difficult recovery, and difficult synergistic optimization of catalytic efficiency in high-value conversion of biomass, this study utilizes mineralization self-assembly technology to combine laccase with Fe₃O₄@SiO₂-PMIDA-Cu²⁺ composite, constructing magnetic laccase nanoflower (MLac-NFs) materials with a porous structure and superparamagnetism. This synthetic material can efficiently catalyze the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The characterization results indicated that MLac-NFs exhibit optimal catalytic activity (63.4 U mg⁻¹) under conditions of pH 6.0 and 40 °C, with significantly enhanced storage stability (retaining 94.26% of activity after 30 days of storage at 4 °C). Apparent kinetic analysis reveals that the substrate affinity and maximum reaction rate of MLac-NFs were increased by 38.3% and 439.6%, respectively. In the laccase–mediator system (LMS), MLac-NFs mediated by 30 mM TEMPO could achieve complete conversion of HMF to FDCA within 24 h. Moreover, due to the introduction of magnetic nanoparticles, the MLac-NFs could be recovered and reused via an external magnetic field, maintaining 53.26% of the initial FDCA yield after six cycles. Full article

2,5-bis(hydroxymethy)lfuran (BHMF), a renewable compound with extensive industrial applications, can be obtained by selective hydrogenation of the C=O group of 5-hydroxymethylfurfural (HMF), a platform molecule derived from lignocellulosic biomass. In this work, we perform kinetic modeling of the selective liquid-phase hydrogenation of HMF to BHMF over a Cu/SiO₂ catalyst prepared by precipitation–deposition (PD) at a constant pH. Physicochemical characterization, using different techniques, confirms that the Cu/SiO₂–PD catalyst is formed by copper metallic nanoparticles of 3–5 nm in size highly dispersed on the SiO₂ surface. Before the kinetic study, the Cu/SiO₂-PD catalyst was evaluated in three solvents: tetrahydrofuran (THF), 2-propanol (2-POH), and water. The pattern of catalytic activity and BHMF yield for the different solvents was THF > 2-POH > H₂O. In addition, selectivity to BHF was the highest in THF. Thus, THF was chosen for further kinetic study. Several experiments were carried out by varying the initial HMF concentration (C⁰_HMF) between 0.02 and 0.26 M and the hydrogen pressure (P_H2) between 200 and 1500 kPa. In all experiments, BHMF selectivity was 97–99%. By pseudo-homogeneous modeling, an apparent reaction order with respect to HFM close to 1 was estimated for a C⁰_HMF between 0.02 M and 0.065 M, while when higher than 0.065 M, the apparent reaction order changed to 0. The apparent reaction order with respect to H₂ was nearly 0 when C⁰_HMF = 0.13 M, while for C⁰_HMF = 0.04 M, it was close to 1. The reaction orders estimated suggest that HMF is strongly absorbed on the catalyst surface, and thus total active site coverage is reached when the C⁰_HMF is higher than 0.065 M. Several Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic models were proposed, tested against experimental data, and statistically compared. The best fitting of the experimental data was obtained with an LHHW model that considered non-competitive H₂ and HMF chemisorption and strong chemisorption of reactant and product molecules on copper metallic active sites. This model predicts both the catalytic performance of Cu/SiO₂-PD and its deactivation during liquid-phase HMF hydrogenation. Full article