Bifunctional lignosulfonate-based catalysts (LS-M) with Lewis acid and basic sites were designed and prepared by immobilizing metal ions on lignosulfonate. Catalysts were characterized by XRD, XPS, ...SEM, EDX, TEM, TGA, NH3/CO2-TPD and FTIR, and applied in transformation of carbohydrate biomass to furan derivatives (HMF/furfural) in mixed water/THF systems. With LS-Cr as catalyst, the optimized yields of HMF from cellulose, glucose and mannose were 46.3%, 60.4% and 68.8%, and that of furfural from xylan, xylose and arabinose were 40.2%, 73.1% and 51.6%, respectively. The catalysts could be easily recycled with negligible wastage of the active metal ions.
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•Sustainable and comprehensive utilization of lignocellulose was achieved.•Bifunctional LS-M catalysts with Lewis acid and basic sites were prepared.•LS-Cr showed high yields of HMF/furfural from saccharides in water/THF systems.•The catalyst could be recycled with negligible wastage of the active metal ions.
Conversion of cellulose to the platform chemical, 5‐hydroxymethylfurfural (HMF), is of importance to the manufacture of a variety of bio‐chemicals and biofuels. However, low mass and heat transfer ...between a solid catalyst and the cellulose particles severely hampers the efficiency of cellulose conversion. In effort to conquer the obstacle, a series of N‐doped mesoporous carbon materials (MCNs) were prepared and employed to catalyze cellulose to HMF by use of the temperature‐responsive HCl‐releasing effect of MCNs. In this way, acid‐base dual catalytic environments can be constructed for efficient conversion of cellulose to HMF. MCN‐2‐DH⋅nHCl is capable of adsorbing chemically 1.07 mmol HCl/g at room temperature and releasing about 1.01 mmol HCl/g when being heated to 220 °C. It is found that MCN‐2‐DH⋅nHCl is an excellent catalyst for cellulose conversion, yielding 52.6% HMF, 27.6% reducing sugars and 4.1% levulinic acid with a cellulose conversion of 96.4% after reacting at 220 °C for 80 min. A total carbon yield of 84.3% can be achieved. Moreover, four times of recycling tests demonstrate that MCN‐2‐DH⋅nHCl possesses good temperature‐responsive stability in aqueous solution.
Temperature‐responsive solid acid catalysts provide a novel and green solid‐liquid phase cellulose conversion reaction system. It can release HCl at high temperature and recovery HCl after cooling.
We report herein a new methodology for the rapid and selective reduction of carbonyls in the solid phase. By exploiting mechanical energy and using a cheap and air-stable silane, ...polymethylhydrosiloxane (PMHS), we can reduce a variety of carbonyl compounds, with catalytic amounts of fluorides. A scope of 19 substrates was explored to probe the generality of the method. In addition, an important biomass-based platform chemical, 5-hydroxymethylfurfural (5-HMF), and an insoluble polymer, polyketone, could be reduced with this methodology. A mechanistic study is also presented, suggesting the active role of volatile silane species. This method is particularly appealing to overcome substrate solubility issues and reduce solvent reliance in organic synthesis.
► MCC was hydrolyzed into furans efficiently catalyzing by MnCl2 in various ionic liquids. ► The acidity and structure of ILs were important aspects for MCC hydrolysis. ► SO3H-functionalized ionic ...liquids showed higher activity than non-functionalized ILs. ► A mechanism was proposed to explain the promoting catalysis of MnCl2 in MnCl2–ILs system.
Influence of acidity and structure of ionic liquids on microcrystalline cellulose (MCC) hydrolysis was investigated. MnCl2-containing ionic liquids (ILs) were efficient catalysts and achieved MCC conversion rates of 91.2% and selectivities for 5-hydroxymethyl furfural (HMF), furfural and levulinic acid (LA) of 45.7%, 26.2% and 10.5%, respectively. X-ray diffractometry indicated that catalytic hydrolysis of MCC in ionic liquids resulted in the changes to MCC crystallinity and transformation of cellulose I into cellulose II. SO3H-functionalized ionic liquids showed higher activities than non-functionalized ILs. The simplicity of the chemical transformation of cellulose provides a new approach for the use this polymer as raw material for renewable energy and chemical industries.
La miel de abeja es una compleja mezcla de carbohidratos y de otros compuestos naturales elaborados por diferentes especies del género de abejas Apis, entre ellas, Apis mellífera. La importancia de ...este suplemento dietético potencial se debe a los beneficios terapéuticos, profilácticos, cosméticos y nutricionales como resultado de sus propiedades fisicoquímicas. Por consiguiente, el objetivo que se planteó en esta propuesta investigativa fue el análisis de los factores que determinan las propiedades fisicoquímicas de la miel de abejas. Para ello, se realizó una revisión sistemática de literatura (rsl) utilizando bases de datos, tales como: Scopus, SciELO y Redalyc. La categoría de análisis que se definió fue las publicaciones científicas relacionadas con los factores que determinan las propiedades fisicoquímicas de la miel de abejas. La información obtenida se organizó en una matriz en Excel, y el procesamiento se hizo en el software de minería de texto Vantage Point; para correlacionar las variables y condensar el análisis de los resultados mediante tablas. Los factores determinantes más importantes encontrados fueron: fuente floral, origen botánico, origen geográfico, néctar, clima, tiempo de maduración, condiciones biofísicas de la región, especie de abeja, procesamiento y condiciones de almacenamiento. En conclusión, estos factores influyen determinantemente sobre los valores promedios reportados de algunas propiedades fisicoquímicas como: acidez libre, actividad de diastasa, azúcares reductores, cenizas, color instrumental Pfund, conductividad eléctrica (ce), hidroximetilfurfural (hmf), humedad, pH, sacarosa, gravedad específica, sólidos solubles totales (sst), proteínas, fructosa/glucosa, fructosa, maltosa, viscosidad, acidez titulable, actividad del agua (aw), sólidos totales y actividad antioxidante, entre otras.
The major drawback of chemical transformations for the production of 2, 5-furan dicarboxylic acid (FDCA) implies the usage of hazardous chemicals, high temperature and high pressure from nonrenewable ...resources. Alternate to chemical methods, biological methods are promising. Microbial FDCA production is improved through engineering approaches of media conditions, homologous and heterologous expression of genes, genetic and metabolic engineering, etc. The highest FDCA production of 41.29 g/L is observed by an engineered Raultella ornitholytica BF 60 from 35 g/L HMF in sodium phosphate buffer with a 95.14% yield in 72 h. Also, an enzyme cascade system of recombinant and wild enzymes like periplasmic aldehyde oxidase ABC, galactose oxidase M3-5, HRP and catalase have transformed 6.3 g/L HMF to 7.81 g/L FDCA in phosphate buffer with 100% yield in 6 h. Still, these processes are emerging for fulfilling the industrial needs due to the challenges in 'green FDCA production'.
Honey is a natural food substance considered among functional foods due to its positive effect on human health. Quality of honey is significantly influenced by environmental conditions and botanical ...origin. This study aimed to determine the element content in honey from Kars, Turkey, as well as the bioactive compounds and certain physicochemical and biochemical properties such as hydroxymethylfurfural (HMF) and color in a chemometric approach. In this study, a total of 41 local honey samples were analyzed. The levels of elements Al, As, B, Cd, Cr, Cu, Fe, Mg, Zn, and Pb were determined by inductively coupled plasma optical emission spectrophotometer (ICP-OES). The mean concentrations of the elements in the samples were identified as 3.09, 0.64, 59.07, 0.02, 0.14, 0.17, 1.76, 9.32, 0.78, and 0.33 µg/g for Al, As, B, Cd, Cr, Cu, Fe, Mg, Zn, and Pb, respectively. The mean bioactive compounds of the honey samples were determined as phenolic content (19.74 mg GAE/100 g), flavonoid content (4.47 mg CE/100 mg), and DPPH (49.08% inhibition). The HMF levels of all samples conformed to the honey standards of the Codex Alimentarius and Turkish Food Codex. HMF was not negatively correlated with the other color parameters except for the a* (redness or greenness) value. This study showed that clustering analysis (CA) and principal component analysis (PCA) are useful for distinguishing the originality of honey samples by using element content, bioactive properties, HMF, and color and were useful in defining the Kars honey type.
The genes involved in the aerobic bacterial metabolism of furfural and 5-hydroxymethylfurfural (HMF) have been characterized in two species,
Pseudomonas putida
Fu1 and
Cupriavidus basilensis
HMF14. A ...third furan-metabolizing strain,
Pseudomonas putida
ALS1267, was recently identified that grows robustly on both furfural and HMF as sole carbon sources, with a growth rate of 0.250 h
−1
on furfural and 0.311 h
−1
on HMF, and we have characterized the genes involved in furfural and HMF metabolism in this bacterium. Unlike
C. basilensis
HMF14, which contains separate furfural and HMF operons,
P. putida
ALS1267 contains one contiguous 18.1-kb operon, which harbors all of the furfural- and HMF-metabolizing genes except for one, the
hmfH
gene that encodes HMF/furfural oxidoreductase and has both HMF acid oxidase and furfural/HMF dehydrogenase activity. The 18.1-kb operon was cloned into
P. putida
KT2440, which cannot metabolize furans, enabling growth on furfural as the sole carbon source with a growth rate of 0.340 h
−1
. The clone did not allow
P. putida
KT2440 to metabolize HMF, most likely due to the lack of the
hmfH
gene. No
hmfH
homolog was identified in
P. putida
ALS1267, suggesting that another gene in the ALS1267 genome provides this function.
The sugar dehydration products, furfural and 5-(hydroxymethyl)furfural (HMF), are commonly formed during high-temperature processing of lignocellulose, most often in thermochemical pretreatment, ...liquefaction, or pyrolysis. Typically, these two aldehydes are considered major inhibitors in microbial conversion processes. Many microbes can convert these compounds to their less toxic, dead-end alcohol counterparts, furfuryl alcohol and 5-(hydroxymethyl)furfuryl alcohol. Recently, the genes responsible for aerobic catabolism of furfural and HMF were discovered in Cupriavidus basilensis HMF14 to enable complete conversion of these compounds to the TCA cycle intermediate, 2-oxo-glutarate. In this work, we engineer the robust soil microbe, Pseudomonas putida KT2440, to utilize furfural and HMF as sole carbon and energy sources via complete genomic integration of the 12kB hmf gene cluster previously reported from Burkholderia phytofirmans. The common intermediate, 2-furoic acid, is shown to be a bottleneck for both furfural and HMF metabolism. When cultured on biomass hydrolysate containing representative amounts of furfural and HMF from dilute-acid pretreatment, the engineered strain outperforms the wild type microbe in terms of reduced lag time and enhanced growth rates due to catabolism of furfural and HMF. Overall, this study demonstrates that an approach for biological conversion of furfural and HMF, relative to the typical production of dead-end alcohols, enables both enhanced carbon conversion and substantially improves tolerance to hydrolysate inhibitors. This approach should find general utility both in emerging aerobic processes for the production of fuels and chemicals from biomass-derived sugars and in the biological conversion of high-temperature biomass streams from liquefaction or pyrolysis where furfural and HMF are much more abundant than in biomass hydrolysates from pretreatment.
•HMF and furfural are common microbial inhibitors in biomass conversion.•HMF and furfural gene cluster was isolated from Burkholderia phytofirmans..•We heterologously express the HMF/furfural gene cluster in Pseudomonas putida..•Expression enables cultivation on HMF and furfural as a sole carbon source.•Expression also enables enhanced conversion on lignocellulosic hydrolysate.
•Ultrasound-assisted ultra-wet (US-UWet) impregnation synthetic method is presented.•Mixed cupric and cuprous oxides nanoclusters (< 4 nm) were decorated on TiO2 P25.•The nanocomposite showed H2 ...formation capability under low power UV irradiation.•The additive free oxidation of biomass derived model platform chemicals was studied.•Nanocomposite revealed higher selectivity comparing to P25 for HMF and BnOH oxidation.
The herein presented ultrasound-assisted ultra-wet (US-UWet) impregnation synthetic approach was followed in order to avoid the drawbacks of the conventional wet impregnation synthesis. The goal was to homogeneously decorate the surface of the TiO2 nanoparticles with nanometric sized (< 4 nm) clusters of mixed cupric and cuprous oxides. The physicochemical features of the nanocomposite (TiO2CuOx) were determined by high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and Diffuse reflectance (DR) spectroscopy. TiO2CuOx showed an enhanced and continuous capability to generate molecular hydrogen upon low power ultraviolet irradiation. The benchmark commercial TiO2 P25 did not reveal any H2 formation under these conditions. TiO2CuOx presented also a high efficiency for the additives-free selective partial oxidation of two well established biomass derived model platform chemicals/building blocks, 5-hydroxymethylfurfural (HMF) and benzyl alcohol (BnOH) to the value-added chemicals 2,5-diformylfuran (DFF) and benzyl aldehyde (PhCHO), respectively. The nanocomposite showed higher DFF and PhCHO yield compared to P25.
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