2-furancarboxylic Acid Research Articles

Direct catalytic conversion of bagasse fibers to furan building blocks in organic and ionic solvents

The applications of lignocellulosic wastes to produce a wide variety of products, including biochemicals, biomaterials, and biofuels, can be an effective solution for utilizing these valuable waste materials. In this study, the production of furan building blocks from bagasse fibers was investigated by treating unbleached fibers with NMMO, [Bmim]Cl, and TMAH at different temperatures using AlCl3 and CrCl2 as the catalysts. The resulted liquors were extracted with CH2Cl2 to obtain furan rich fraction. Analysis of extracted fractions with GC/MS indicates the production of various furanic compounds due to catalytic solvolysis with different solvents at elevated temperatures. 2(3H)-Furanone and 2-methyl-THF were the main products of catalytic treatment of bagasse fibers with NMMO. Treatment by [Bmim]Cl resulted in 2,5-dihydro furanone as the dominant product at elevated temperatures. Furan carboxylic acid methyl ester and 2,5-furan dicarboxylic acid dimethyl ester were the main TMAH reaction products with unbleached fibers. The results indicate that the type of solvent affects the solvolysis rate and dehydration of cellulose to furanic compounds. Moreover, increasing the temperature led to an increase in the formation of the furanic compounds.Graphical abstract

RIFM fragrance ingredient safety assessment, 2-furancarboxylic acid, tetrahydro-, ethyl ester, CAS Registry Number 16874-34-3

• 2-Furancarboxylic acid, tetrahydro-, ethyl ester; a safety assessment based on RIFM's criteria. • A safety assessment based on 7 human health endpoints plus environmental. • All endpoints were cleared using target data, read-across, and/or TTC.

Changes in aroma components and potential Maillard reaction products during the stir-frying of pork slices

Stir-fried pork slices are kinds of traditional pork processing products in China, which are usually cooked at high temperature with different seasonings. Because of their special quality and flavor, these products gain consumers' preference. However, there are few studies on their physicochemical properties, aroma composition and safety. In this study, the changes in basic components, aroma components and potentially hazardous substances during the stir-frying of pork slices were determined. The effects of the different ratios of fat meat to lean meat and vinegar on these indicators were evaluated, and the formation of potential Maillard reaction products was also analyzed. The results indicated that water content, chrominance values of L* and b* exhibited decreasing trends; a* value displayed a trend of decline first and then rising, while the fat content showed a rising trend during the processing. Appropriate stir-frying can promote the formation of aldehydes, while the content of acids, ketones, and terpenes decreased during processing. The change of alcohols has no obvious rule. Some sulfur compounds not found in raw meat were also detected. Different ratios of fat meat and lean meat changed the kinds of aroma components, while vinegar altered the types and their contents. Besides, the contents of acrylamide and 5-HMF changed significantly, and that of benzo(a)pyrene remained at a low level. The addition of vinegar can enhance the amount of acrylamide and 5-HMF but has no obvious effect on benzo(a)pyrene. Besides, 8 kinds of Maillard reaction products (acrylamide, 5-HMF, benzo(a)pyrene, 5-methylfurfural, pyrazine, 4-methylimidazole, pyrraline, and 5- hydroxymethyl - 2-furancarboxylic acid) were determined, and some of them were harmful to product quality and human health. The results showed that the processing time of pork slices should be controlled within 60 min.

Antimicrobial Furancarboxylic Acids from a Penicillium sp.

Ten novel (1, 2, 3a, 3b, 4a, 4b, 5a, 5b, 6a, and 6b) furancarboxylic acids including four pairs of epimers (3a, 3b; 4a, 4b; 5a, 5b; 6a, 6b), together with seven known analogues (7a, 7b, 8a, 8b, 9a, 9b, and 10), were isolated from the fermentation of the soil-derived fungus Penicillium sp. sb62. Their structures were established on the basis of spectroscopic data analysis, and the absolute configurations were determined by time-dependent density functional theory electronic circular dichroism calculations, comparison of the specific optical rotation values, and modified Mosher's method. Compounds 1-4 represent the first class of natural furancarboxylic acids featuring a thiophene moiety. Compounds 1-7 showed antimicrobial inhibitory activities against Escherichia coli, Staphylococcus aureus, and Candida albicans with MIC values ranging from 0.9 to 7.0 μg/mL, from 1.7 to 3.5 μg/mL, and from 3.3 to 7.0 μg/mL, respectively.

Evaluation of ionic equilibria in mixed-buffer isothermal titration calorimetry and continuously stirred tank reactors

Determination of an equilibrium pH value in complex aqueous solution and deconvolution of this equilibrium to evaluate phenomena related to mixing, dilution, or progress of reaction is increasingly important in areas ranging from water quality to pharmaceutical formulations and manufacturing. Linearization of pH problems by simple algebraic substitution enables equilibria within complex buffered aqueous solutions to be modeled as an eigenvalue problem. This formulation approach makes rigorous determination of equilibrium pH values and reactor dynamics more accessible than with previous calculation methods, even when activity coefficients and non-ideality are considered. This work demonstrates how such calculations can enable detailed modeling of enthalpic changes in an isothermal titration calorimeter. In support of this work, the acid dissociation constants for three furancarboxylic acids (2-furancarboxylic acid, FA; 5-formyl-2-furancarboxylic acid, FFA; and 2,5-furandicarboxylic acid, FDCA), two of them novel, were determined and compared with multi-wavelength ultraviolet–visible spectrophotometry. The thermodynamic pKa values were determined to be 3.1 for FA, 2.2 for FFA, and 2.1 and 3.4 for the first and second ionization steps of FDCA, respectively.

Cascade conversion of furancarboxylic acid to butanediol diacetate over Pd/C and La(OTf)3 catalytic system

The conversion of biomass to a high value-added product 1, 4-butanediol (BDO) and its derivatives is of great economic significance. In this work, furancarboxylic acid (FCA) was adopted as the raw material to prepare BDO. The one-pot synthesis of 1, 4-butanediol diacetate (BDA) has been successfully prepared from FCA with metal triflates and Pd/C catalysts. The effect of reaction conditions was investigated and the reaction routes was systematically studied by 1H-NMR and GC. The tandem catalytic process from FCA to BDA mainly underwent three stages. Firstly, FCA was hydrogenated to tetrahydrofurfuric acid (THFCA) by Pd/C. Afterwards, THFCA was decarbonylated to form oxonium ions with metal triflates. Then the oxonium ions was rapidly hydrogenated to form tetrahydrofuran (THF) by Pd/C. Ultimately, THF was ring-opening esterified to BDA by metal triflates. This novel synthesis method of BDO from FCA provides a promising protocol for broadening the application of common biomass substrates.

Selective Biosynthesis of Furoic Acid From Furfural by Pseudomonas Putida and Identification of Molybdate Transporter Involvement in Furfural Oxidation.

Upgrading of furanic aldehydes to their corresponding furancarboxylic acids has received considerable interest recently. Herein we reported selective oxidation of furfural (FAL) to furoic acid (FA) with quantitative yield using whole-cells of Pseudomonas putida KT2440. The biocatalytic capacity could be substantially promoted through adding 5-hydroxymethylfurfural into media at the middle exponential growth phase. The reaction pH and cell dosage had notable impacts on both FA titer and selectivity. Based on the validation of key factors for FAL conversion, the capacity of P. putida KT2440 to produce FAL was substantially improved. In batch bioconversion, 170 mM FA was produced with selectivity nearly 100% in 2 h, whereas 204 mM FA was produced with selectivity above 97% in 3 h in fed-batch bioconversion. Particularly, the role of molybdate transporter in oxidation of FAL and 5-hydroxymethylfurfural was demonstrated for the first time. The furancarboxylic acids synthesis was repressed markedly by destroying molybdate transporter, which implied Mo-dependent enzyme/molybdoenzyme played pivotal role in such oxidation reactions. This research further highlights the potential of P. putida KT2440 as next generation industrial workhorse and provides a novel understanding of molybdoenzyme in oxidation of furanic aldehydes.

Pre-treatment with D942, a furancarboxylic acid derivative, increases desiccation tolerance in an anhydrobiotic tardigrade Hypsibiusexemplaris.

The tardigrade Hypsibiusexemplaris can undergo anhydrobiosis. Several chemicals that inhibit successful anhydrobiosis in H.exemplaris have been identified, and these chemicals inhibit the activity of signaling molecules. In the present study, we investigated whether upregulation of the activity of these signaling molecules could improve desiccation tolerance of H.exemplaris. Pre-treatment with an indirect activator of AMP-activated protein kinase [AMPK; which directly inhibits mammalian NAD(P)H dehydrogenase [quinone] 1 [NQO1] of mitochondrial complex I (D942)] significantly improved desiccation tolerance of H.exemplaris, whereas a direct activator of AMPK did not. To elucidate the underlying molecular mechanisms, we examined the proteome of tardigrades treated with D942. Two proteins, putative glutathione S-transferase and pirin-like protein, were upregulated by treatment. Both of these proteins are known to be associated with the response to oxidative stress. One of the downregulated proteins was serine/threonine-proteinphosphatase 2A (PP2A) 65-kDa regulatory subunit A alpha isoform, and it is interesting to note that PP2A activity was previously suggested to be required for successful anhydrobiosis in H.exemplaris. Taken together, our results suggest that D942 treatment may partially induce responses common to those of desiccation stress. The identification of a chemical that improves desiccation tolerance of H.exemplaris may facilitate further investigation into desiccation tolerance mechanisms.

Bioisostere Modifications of Cu2+ and Zn2+ with Pyromucic Acid Anions and N-Donors: Synthesis, Structures, Thermal Properties, and Biological Activity

Mono- and binuclear complexes [Cu(Fur)2(Phen)] (I), [Cu2(Fur)4(Py)2] (II), [Cu(Fur)2-(Py)2(H2O)] (III), and [Zn2(Fur)4L2] (L = Py (IV), Phpy (V)) are synthesized using the reactions of copper(II) and zinc(II) acetates with anions of pyromucic acid (2-furancarboxylic acid (HFur)) and N‑donor ligands (pyridine (Py), 4-phenylpyridine (Phpy), and 1,10-phenanthroline (Phen)) in acetonitrile. The copper complexes with pyridine are successively formed from the same reaction mixture: at first binuclear complex II is formed and then mononuclear complex III is formed. All compounds are isolated as single crystals, and their structures are determined by X-ray structure analysis (CIF files CCDC nos. 1974386 (I), 1974388 (II), 1974389 (III), 1974387 (IV), and 1974385 (V)). The thermal behavior of complexes II and III is studied by simultaneous thermal analysis. The biological activity in vitro of all complexes is determined toward the nonpathogenic mycobacterial strain Mycolicibacterium smegmatis. Complexes I and V exhibit a high biological activity and are promising for further studies of antitubercular activity.

Furan Carboxylic Acids Production with High Productivity by Cofactor‐engineered Whole‐cell Biocatalysts

AbstractFuran carboxylic acids are useful chemicals in various industries. In this work, biocatalytic production of furan carboxylic acids was reported with high productivities by cofactor‐engineered Escherichia coli cells. NADH oxidase (NOX) was introduced into E. coli harboring aldehyde dehydrogenases (ALDHs) to promote intracellular NAD+ regeneration, thus significantly enhancing ALDH‐catalyzed oxidation. These engineered biocatalysts were capable of efficient aerobic oxidation of a variety of aromatic aldehydes. More importantly, they exhibited high substrate tolerance toward toxic furans. E. coli co‐expressing vanillin dehydrogenase and NOX (E. coli_CtVDH1_NOX) enabled efficient oxidation of 250 mM of 5‐hydroxymethylfurfural (HMF) to 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA), providing a productivity of 3.7 g/L h. With E. coli_CtVDH2_NOX as catalyst, up to 240 mM of furfural and 5‐methoxymethylfurfural (MMF) could be smoothly oxidized. 2‐Furoic acid (FCA, 227 mM) and 5‐methoxymethyl‐2‐furancarboxylic acid (MMFCA, 287 mM) were produced in fed‐batch synthesis, providing the productivities of 2.0 and 5.6 g/L h, respectively.

Biocatalytic Oxidation of Biobased Furan Aldehydes: Comparison of Toxicity and Inhibition of Furans toward a Whole-Cell Biocatalyst

Furan carboxylic acids are promising and renewable building blocks in polymer and pharmaceutical industries. In this work, biocatalytic synthesis of furan carboxylic acids was performed from biobas...

Uncovering the reactive nature of 4-deoxy-l-erythro-5-hexoseulose uronate for the utilization of alginate, a promising marine biopolymer

Alginate is a linear polyuronate in brown macroalgae. It is also a promising marine biopolymer that can be degraded by exo-type alginate lyase into an unsaturated uronate that is non-enzymatically or enzymatically converted to 4-deoxy-l-erythro-5-hexoseulose uronate (DEH). In a bioengineered yeast Saccharomyces cerevisiae (DEH++) strain that utilizes DEH, DEH is not only an important physiological metabolite but also a promising carbon source for biorefinery systems. In this study, we uncovered the essential chemical nature of DEH. In particular, we showed that DEH non-enzymatically reacts with specific amino groups in Tris, ammonium salts [(NH4)2SO4 and NH4Cl], and certain amino acids (e.g., Gly, Ser, Gln, Thr, and Lys) at 30 °C and forms other compounds, one of which we tentatively named DEH-related product-1 (DRP-1). In contrast, Asn, Met, Glu, and Arg were almost inert and Ala, Pro, Leu, Ile, Phe, Val, and Asp, as well as sodium nitrate (NaNO3), were inert in the presence of DEH. Some of the above amino acids (Asn, Glu, Ala, Pro, Phe, and Asp) were suitable nitrogen sources for the DEH++ yeast strain, whereas ammonium salts and Ser, Gln, and Thr were poor nitrogen sources owing to their high reactivity to DEH. Nutrient-rich YP medium with 1% (w/v) Yeast extract and 2% (w/v) Tryptone, as well as 10-fold diluted YP medium, could also be effectively used as nitrogen sources. Finally, we identified DRP-1 as a 2-furancarboxylic acid and showed that it has a growth-inhibitory effect on the DEH++ yeast strain. These results show the reactive nature of DEH and suggest a basis for selecting nitrogen sources for use with DEH and alginate in biorefineries. Our results also provide insight into the physiological utilization of DEH. The environmental source of 2-furancarboxylic acid is also discussed.

Efficient synthesis of 5-hydroxymethyl-2-furancarboxylic acid by Escherichia coli overexpressing aldehyde dehydrogenases

Catalytic transformation of biomass-derived furans into value-added chemicals and biofuels has received considerable interest recently. In this work, aldehyde dehydrogenases (ALDHs) were identified from Comamonas testosteroni SC1588 for the oxidation of bio-based furans into furan carboxylic acids. Of the whole-cell biocatalysts constructed, Escherichia coli expressing a vanillin dehydrogenase (E. coli_CtVDH1) proved to be the best for the oxidation of 5-hydroxymethylfurfural (HMF). 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) was obtained in the yield of approximately 92 % within 12 h using this recombinant strain when the HMF concentration was up to 200 mM. In a fed-batch process, 292 mM of HMFCA was produced within 20.5 h, thereby providing a productivity as high as 2.0 g/L h. Other furan carboxylic acids were synthesized in the yields of 83–95%. Besides, the partially purified HMF was smoothly converted into HMFCA by this recombinant strain, with a 90% yield.

Selective Hydrogenolysis of α-C–O Bond in Biomass-Derived 2-Furancarboxylic Acid to 5-Hydroxyvaleric Acid on Supported Pt Catalysts at Near-Ambient Temperature

Hydrogenolysis of the α-C–O bond in abundantly available biomass-based furfural and its derivatives provides a viable route for sustainable synthesis of valuable C5 compounds, particularly with two...

Inherited Epidermolysis Bullosa: creation a desease model with CRISPR/Cas9 system

Catalytic transformation of biomass-derived furans into value-added chemicals and biofuels has received considerable interest recently. In this work, aldehyde dehydrogenases (ALDHs) were identified from Comamonas testosteroni SC1588 for the oxidation of bio-based furans into furan carboxylic acids. Of the whole-cell biocatalysts constructed, Escherichia coli expressing a vanillin dehydrogenase (E. coli_CtVDH1) proved to be the best for the oxidation of 5-hydroxymethylfurfural (HMF). 5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) was obtained in the yield of approximately 92 % within 12 h using this recombinant strain when the HMF concentration was up to 200 mM. In a fed-batch process, 292 mM of HMFCA was produced within 20.5 h, thereby providing a productivity as high as 2.0 g/L h. Other furan carboxylic acids were synthesized in the yields of 83–95%. Besides, the partially purified HMF was smoothly converted into HMFCA by this recombinant strain, with a 90% yield.

One-Pot Enzyme Cascade for Controlled Synthesis of Furancarboxylic Acids from 5-Hydroxymethylfurfural by H2 O2 Internal Recycling.

Furancarboxylic acids are promising biobased building blocks in pharmaceutical and polymer industries. In this work, dual-enzyme cascade systems composed of galactose oxidase (GOase) and alcohol dehydrogenases (ADHs) are constructed for controlled synthesis of 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) from 5-hydroxymethylfurfural (HMF), based on the catalytic promiscuity of ADHs. The byproduct H2 O2 , which is produced in GOase-catalyzed oxidation of HMF to 2,5-diformylfuran (DFF), is used for horseradish peroxidase (HRP)-mediated regeneration of the oxidized nicotinamide cofactors for subsequent oxidation of DFF promoted by an ADH, thus implementing H2 O2 internal recycling. The desired products FFCA and FDCA are obtained with yields of more than 95 %.

Structure and Mechanism of Titania-Supported Platinum–Molybdenum Catalyst for Hydrodeoxygenation of 2-Furancarboxylic Acid to Valeric Acid

Selective hydrodeoxygenation of 2-furancarboxylic acid, which can be a relatively stable platform chemical from hemicellulose, to valeric acid was investigated in detail, and the reaction has been ...

Valorization of C5 polyols by direct carboxylation to FDCA: Synthesis and characterization of a key intermediate and role of carbon dioxide

Replacing fossil-C based plastics with those derived from renewable-C is one of the goals of the modern polymer industry. 2,5-Furan dicarboxylic acid (2,5-FDCA) is a candidate to substitute terephthalic acid as comonomer for polyesters. 2,5-FDCA is usually produced from C6 sugars. Carboxylation of 2-furancarboxylic acid (2-FCA) to 2,5-FDCA is an alternative synthetic approach to such monomer for polyethene furoate (PEF) preparation. In this work, several inorganic carbonates have been tested in the 2-FCA carboxylation in presence and absence of CO2. A key copper intermediate has been synthesized and fully characterized that is able to increase the acidity and, thus, the reactivity of 5-H towards a carbonate species. Carboxylation occurs at 93% yield in absence of CO2. The role of metal salts and CO2 were investigated. The conversion yield of 2-FCA into the dicarboxylic acid is related to the charge density on the metal cation, increasing with lower charge-density.

Significantly improved oxidation of bio-based furans into furan carboxylic acids using substrate-adapted whole cells

Abstract Furan carboxylic acids are important building blocks in polymer and fine chemical industries. In this work, a simple substrate adaptation strategy was applied to improve the catalytic performances of Comamonas testosteroni SC1588 cells for the synthesis of various furan carboxylic acids. It was found that biocatalytic synthesis of 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) was substantially promoted by adding histidine and increasing cell concentrations. HMFCA was produced in a quantitative yield from 200 mM HMF in 24 h. Besides, the HMFCA yields of 71%–81% were achieved with the substrate concentrations up to 250–300 mM. It was firstly found that 4-tert-butylcatechol (TBC), as the stabilizer present in HMF, exerted a significantly detrimental effect on whole-cell catalytic synthesis of HMFCA at high substrate concentrations (more than 130 mM). In addition, a variety of furan carboxylic acids such as 2-furoic acid, 5-methyl-2-furancarboxylic acid and 5-methoxymethyl-2-furancarboxylic acid were synthesized with the yields up to 98%.

Intramolecular Diels–Alder and [3+2] Cycloaddition Reactions in the One-Pot Synthesis of Epoxypyrrolo[3,4-g]indazoles

A one-pot approach for the synthesis of epoxypyrrolo[3,4-g]indazoles is presented. The first step was initiated by a three-component reaction of an isocyanide, a dialkyl acetylenedicarboxylate, and 2-furancarboxylic acid, and led to 1,3-dioxoepoxyisoindole, followed by the addition of hydrazonoyl chloride through a [3+2]-cycloaddition reaction in the second step. The key step in the formation of final compound involves a bicyclization strategy through intramolecular Diels–Alder­ (IMDA) reaction.