Instituto de Tecnología Química

Ongoing research on adsorbent deactivation in dryingprocesseshas unveiled crucial insights into the loss of performance with prolongeduse. Our study builds on previous work by examining the effects ofhigh temperatures, hydrocarbon exposure, and cycle duration on chabaziteadsorbents with a Si/Al ratio of approximately 2 and in the sodiumform. By aging the material under controlled conditions, we assessedthe impact on its structural and textural properties. Our findingsreveal that maintaining high temperatures, coupled with exposure to n-heptane vapor, induces a mild degradation of the crystallinestructure, with more pronounced effects during longer aging periods.Notably, hydrocarbons play a critical role in adsorbent deactivation,adsorbing in both the inner pores and the outer surface of the zeolite.This leads to a deterioration of the textural characteristics, whichdirectly correlates with an increase in the carbon content of thebulk material. Additionally, samples exposed to n-heptane vapor exhibited a more homogeneous composition comparedto those subjected to manual liquid n-heptane addition.Overall, the degree of degradation varies among aged samples, indicatingthe need for tailored applications based on specific aging conditions.

Abstract Carbohydrate-binding modules (CBMs) are widespread auxiliary domains in carbohydrate-active enzymes, yet their contribution to enzyme function and evolvability remains unclear, particularly in redox enzymes. Here, we report the first biochemically and structurally characterized bacterial galactose oxidase. Unlike its fungal counterparts, this enzyme is produced in an active form containing a catalytic Cu(II)–tyrosyl radical cofactor and two N-terminal CBM32 domains. Biochemical, structural, and computational analyses reveal functional asymmetry between the duplicated CBMs, which differentially modulate soluble expression, stability and polysaccharide binding. Deletion of the first CBM markedly enhances solubility while preserving catalytic competence, and binding assays identify this module as the dominant contributor to galactan affinity. Directed evolution promotes CBM truncation and recombination, yielding functional chimeric variants and uncovering a residue influencing polysaccharide recognition. These findings expand the diversity of copper radical oxidases and highlight domain architecture as an evolvable determinant of redox enzyme behavior.

ABSTRACTThe rational design of heterostructured photocatalysts that simultaneously enable efficient carrier separation, photothermal synergy, and controllable reaction pathways is crucial for advancing CO2 conversion. Here, a Ni/Ti3C2Clx MXene heterojunction is synthesized via Lewis acid molten‐salt etching, featuring ultrathin Ni platelets strongly anchored to the MXene substrate through interfacial TiNi3 bonding. This architecture establishes an S‐scheme charge transfer pathway, as evidenced by in situ irradiated X‐ray photoelectron and X‐ray absorption spectroscopy, which confirm efficient carrier transfer and separation, while femtosecond transient absorption spectroscopy reveals ultrafast interfacial dynamics. Under photothermal conditions, the cooperative interplay of metallic Ni, surface NiOx, and the conductive MXene substrate couples directional charge migration with thermally assisted molecular activation and barrier lowering, thereby enabling regulated CO2 hydrogenation product distribution between CH4 and CH3OH. Density functional theory demonstrates that surface‐state evolution, rather than simple oxidation degree, modulates adsorption energetics and alters the relative barriers of CH4 and CH3OH pathways, such that moderately oxidized Ni–NiOx interfacial ensembles favour methanol forming intermediates, whereas extensive oxidation suppresses CH3OH formation. Collectively, these findings demonstrate a robust strategy for exploiting MXene‐based heterojunction interfaces in photothermal catalysis and underscore the pivotal role of surface state regulated reaction pathways in steering product distribution during CO2 hydrogenation.

This work presents a strategy to control not only the distance and proximity of active sites at the atomic or nanoscale but also the nature of sites in zeolite-based catalysts, promoting the coupling rate of surface intermediate species and accordingly the formation rate of dimethyl ether (DME) by a direct CO2 hydrogenation path. We use a one-pot synthesis strategy and a thermal-induced detachment process of framework elements, such as Ga3+ ions, to stabilize PdGa alloys and Ga+ sites in close proximity to Brønsted acid sites under reductive conditions. Using this strategy, a production of oxygenates of up to 42,864 gMeOH+DME·kgPd-1·h-1 at 45 bar, 260 °C, and WHSV = 15,000 mL·gcat-1·h-1, is obtained with 80% selectivity to oxygenated (19% methanol/61% DME), outperforming the most active Pd-based CO2 hydrogenation catalysts in the literature. Time-resolved kinetic studies, in situ X-ray adsorption, and in situ and operando IR offer strong proof of the key role of isolated Ga+ Lewis acid sites in close proximity to Brønsted acid sites in stabilizing monoformate intermediate species and facilitating the direct production of DME. Finally, this work highlights the key role of the zeolite in metal confinement, conferring excellent stability, oxidation resistance, hydrophilicity, and close proximity of active sites together with the stabilization of low-coordinated Lewis acid sites.

The LDHs in the Mg-Al systems containing glyphosate were synthesized by the reconstruction and coprecipitation methods at a constant pH. The XRD data show that the Mg2Al-glyphosate hybrid material was formed in both cases, even though a better crystallinity was achieved from the synthesis conducted by the coprecipitation method. Moreover, vertical glyphosate intercalation can be inferred, given the observed 7.9 Å interlamellar spacing. Solid-state NMR and FT-IR-ATR data corroborate the formation of the material, with significant changes in the spectra of both when comparing the hybrid materials and free glyphosate. Studies involving pH variation showed the greatest glyphosate release at pH 10, reaching approximately 70% and governed by first-order kinetics, confirmed by the simulation model. Experiments involving carbonate, nitrate, and chloride anions suggest that the presence of carbonate has a greater influence on glyphosate release and that an increase in the concentration of this anion also corroborates to an increase in glyphosate release, both of which are also governed by a first-order mechanism.

Abstract Fabricating effective reusable catalysts for biomass deoxygenation is essential for sustainable fuel production. In this study, Ni nanoparticles (15–25 wt%) were incorporated into UiO-66 through solvothermal synthesis, followed by partial carbonization at 300°C to improve thermal stability, dispersion and catalytic efficiency in palm fatty acid distillate deoxygenation. Structural analysis confirmed that the UiO-66 framework remained intact after Ni incorporation, with X-ray photoelectron spectroscopy indicating well-dispersed Ni species (Ni2p3/2 at 855.6–856.7 eV). The acid–base characteristics and high surface area supported the cleavage of C–O and C–C bonds. Among the catalysts tested, C-UiO-66@Ni-20wt% showed the best performance, achieving an 87.65% hydrocarbon yield under conditions (3.14 h, 3.28 wt% catalyst, 340°C) optimized by response surface methodology. The reliability of the model was confirmed by a high R² value (99.47%) and statistical significance (p < 0.0001). The catalyst maintained stable activity over seven cycles, with only a 2–7% yield reduction per cycle, before significant deactivation occurred in the eighth cycle owing to pore blockage and active site agglomeration. This study illustrates that Ni-doped UiO-66, with its balanced acidity, structural integrity and efficiency at low temperatures, is a promising catalyst for scalable biofuel production, offering both high reactivity and reusability.

Biocatalysis has ascended as a defining force in contemporary total synthesis, furnishing catalytic modalities that deliver molecular complexity with unparalleled chemo-, regio-, and stereo-control. As structurally sophisticated therapeutics-including macrocyclic lactones, polyketides, terpenoids, alkaloids, and pharmacologically privileged scaffolds-continue to drive innovation, enzyme-mediated strategies provide mechanistically exquisite, environmentally consonant solutions that increasingly transcend the capabilities of traditional chemical catalysis. This review articulates the unifying principles and activation paradigms through which oxidoreductases, hydrolases, and transferases orchestrate the streamlined construction of architecturally dense natural products. In particular, emphasis is placed on cascade logic, mechanistically integrated chemoenzymatic platforms, and advances in enzyme engineering, which collectively furnish transformative blueprints for accessing next-generation bioactive architectures. By foregrounding conceptual frameworks rather than enumerating examples, this review positions biocatalysis as a central strategic axis at the intersection of synthetic methodology, chemical biology, and therapeutic discovery and as a driving force in shaping the future landscape of complex molecule synthesis (covering 2000-2025).

Integrating foreign metal ions into mixed metal oxide scaffolds, such as CaWO4, by a wet chemistry coprecipitation method is an efficient approach for regulating the chemical composition, which determines the structure and properties and, in turn, offers a versatile platform for enhancements of intrinsic properties and introduction of additional attributes in the host material. In this work, a series of Ca1–xMnxWO4 was prepared via a coprecipitation process at 30 °C to exhibit sphere-like hierarchical structures assembled from individual nanocrystals. The solid solubility limit of Mn in CaWO4 is estimated to be ∼24% for this synthetic approach. The nanocrystals exhibit nonstoichiometric amorphous layers on the surface, which are expected for this type of materials synthesized under such mild conditions. The successful incorporation of Mn into the crystal lattice of CaWO4 led to an isotropic contraction of the crystal unit cells as well as the shifting and merging of several vibrational modes. Cyclic voltammetry confirmed the activity of Ca1–xMnxWO4 for the electrooxidation of glucose, which is directly linked to the presence of Mn in CaWO4. With the highest Mn content, Ca0.759Mn0.241WO4 achieved sensitivities of 3.80 and 1.00 μA·mM–1·cm–2 for glucose concentrations in the ranges of 0.002–0.2 and 0.2–1 mM, respectively, which are 237 and 60 times increases from that of CaWO4. The limit of detection and lower limit of quantitation were estimated to be 14 and 48 μM, respectively, with reasonable reproducibility and repeatability.

Urban PM2.5 samples were collected in Manaus, a major city in the Amazon rainforest, to analyze dicarboxylic acids (DCA) (C2–C9), black carbon (BC), levoglucosan (LEV), and sulfate (SO42–) during daytime and nighttime, in periods with and without smoke over the city from biomass burning (BB). Oxalic acid (C2) was the dominant DCA, followed by malonic acid (C3) and succinic acid (C4). The 12.5% nighttime increase in oxalic acid (C2) and higher C2/TDCA ratio at night indicate ongoing secondary formation, not just accumulation from a lower boundary layer. BC showed a moderate correlation with C4, and, since no correlation was observed between BC and LEV, this suggests that fossil fuel combustion–a recognized source of BC–is one of the possible primary sources of C4 in the studied atmosphere. The phthalic acid (Ph) to azelaic acid (C9) ratio (Ph/C9), an indicator of the dominant oxidative pathway for DCA formation, was lowest at night, and C9 exhibited a strong correlation with levoglucosan (LEV) (r = 0.89), suggesting that BB serves as a major source of primary C9 and may also provide precursors that contribute to the secondary formation of PM2.5. During smoke periods, LEV increased by 479%, while C2 and C3 increased by 247% and 259%, and the ratios of C2/C4 and C2/SO42– increased by 40% and 259%, respectively. Biomass burning has modified the composition of DCAs, possibly influencing aerosol hygroscopicity and their potential to act as cloud condensation nuclei, with possible implications for regional climate. This study highlights the critical role of biomass burning in the formation of organic aerosols and their influence on oxidative pathways, as well as their broader environmental impacts.

Brazil is a country with the greatest biodiversity inthe world,but much of it is still largely unexplored. Trigynaeaaxilliflora (Annonaceae) is a Brazilian plant speciesthat has not been previously studied. This research aimed to characterizethe chemical constituents and evaluate the biological activities ofthe extract, fractions and isolated compounds. Xylopine, a major compoundisolated from this extract, is an aporphine alkaloid and a chemotaxonomicmarker of this family, whose structure was confirmed by 1H/13C NMR and HRESIMS. HPLC-UV-ESI-qTOF dereplicationindicated that xylopine and seven other aporphine alkaloids were presentin the crude extract. A solvent washing procedure allowed the recoveryof 138 mg of xylopine, with a yield of 13.8% (138 mg/g crude extract)and 95% purity by HPLC-DAD. Cytotoxicity by the MTT assay showed thatxylopine was active against MG-63 osteosarcoma cells (IC50 = 5.5 μg/mL), with a selectivity index (SI = 0.63) indicatinga favorable selectivity compared to doxorubicin (SI = 0.22). Antibacterialassays demonstrated the inhibition of Staphylococcusaureus and Escherichia coli by the ethanolic extract and chloroform fraction (MIC 125–500μg/mL), as well as by xylopine (MIC 62.5 μg/mL for S. aureus and 31.2 μg/mL for E. coli). To evaluate antinociceptive activity, theformalin test was used, and both the ethanolic extract and xylopinesignificantly reduced nociceptive behavior during the inflammatoryphase from 123.8 ± 13.7 s (100%) to 71.3 ± 10.2 s (57.5%)and 1.3 ± 0.4 s (1%), respectively, at doses of 30 mg/kg. Insilico pharmacokinetic analysis using SwissADME predicted favorabledrug-likeness and oral bioavailability for xylopine, supporting itspotential as a drug candidate. This study presents the first reporton the chemical profile and bioactivities of T. axilliflora, suggesting it as a possible natural source of xylopine. This findinghighlights the importance of phytochemical and pharmacological researchin understanding Brazil’s understudied flora.