5-hydroxymethylfurfural Research Articles

Mechanism insight into α-D-galactopyranose conversion to 5-hydroxymethyl furfural by combining Py-GC–MS experiments and theoretical calculations

Pyrolysis of biomass is a promising technique for producing various chemicals. During the fast pyrolysis of biomass, 5-hydroxymethyl furfural (5-HMF) is a significant product derived from holocellulose, which consists of cellulose and hemicellulose. In this study, the formation mechanism of 5-HMF was systematically revealed by combining fast pyrolysis experiments of 13C-labeled and unlabeled D-galactose and density functional theory calculations that α-D-galactopyranose was selected as the model compound for hemicellulose. Experimental results show the yield and concentration of 5-HMF gradually decrease as the temperature rises (≥400 °C). In addition, the origin of the C atoms in 5-HMF was determined. The aldehyde group and hydroxymethyl are primarily derived from C1 and C6 of D-galactose, respectively. Based on computational results, α-D-galactopyranose prefers to undergo a ring-opening reaction to form acyclic D-galactose with an energy barrier of 166.5 kJ/mol. (2R,3S,E)-2,3,5,6-tetrahydroxyhex-4-enal (C1-i2) and (2R,3S)-2,3,6-trihydroxy-5-oxohexanal (C1-i3) generated by D-galactose are important intermediates for 5-HMF formation. Because C1-i3 can readily form 5-HMF through successive dehydration at 3-OH+2-H site, cyclization, and dehydration at 5-OH+4-H site. In favorable paths, the aldehyde group of 5-HMF all comes from C1 of α-D-galactopyranose, which reasonably explains the experimental results. Overall, this study will be helpful to improve the formation mechanism of 5-HMF and to develop relevant pyrolysis techniques to prepare it.

Detection of adulteration in Iranian grape molasses added glucose/fructose/sugar beet syrups with 13C/12C isotope ratio analysis method.

Grape molasses (GM), produced from grapes, is a traditional Iranian food and is widely consumed in Iran. However, GM adulteration is among the most widespread illegitimate procedures involving contamination of food with foreign materials, such as adding sugar-water solution, date syrup, sugar beet syrup, and grape sauce. This study used stable carbon 13C/12C isotope ratio analysis method to detect adulteration of GM samples with glucose syrups (GS), fructose syrups (FS), and beet sugar syrups (BS) at the ratio of 0%, 10%, 30%, and 50% (by weight). Physicochemical properties of GM including °Brix, conductivity, specific gravity, pH, moisture content, ash content, hydroxymethyl furfural, sugar content, and rheological properties of samples were investigated. The δ13C isotope ratio of the GM was determined as -26.61%, that of the GS as -13.23%, that of the FS as -13.42%, and that of the BS as -16.58%. The δ13C isotope ratio increased by the addition of adulterant syrups to GM. The addition of each adulterant syrup had a different effect on the physicochemical parameters; however, the °Brix and specific gravity had a positive correlation with the δ13C isotope ratio results. The magnitudes of G' and G" increase with an increase in frequency representing the viscoelastic behavior of samples. The obtained results of this study suggest the use of δ13C isotope ratio method as a fast and accurate method to investigate the adulteration of grape molasses.

Pyrolytic conversion of glucose into hydroxymethylfurfural and furfural: Benchmark quantum-chemical calculations.

Quantum chemical methods have been intensively applied to study the pyrolytic conversion of glucose into hydroxymethylfurfural (HMF) and furfural (FF). Herein, we collect the most relevant mechanistic proposals from the recent literature and organize them into a single reaction network. All the transition structures (TSs) and intermediates are characterized using highly accurate ab initio methods and the possible reaction pathways are assessed in terms of the Gibbs energies of the TSs and intermediates with respect to β-glucopyranose, selecting a 2D ideal-gas standard state at 773 K to represent the pyrolysis conditions. Several pathways can lead to the formation of both HMF and FF passing through rate-determining TSs that have ΔG‡ values of ~49-50 kcal/mol. Both water-assisted mechanisms and nonspecific environmental effects have a minor impact on the Gibbs energy profiles. We find that the HMF → FF + CH2O fragmentation has a small ΔrxnG value and an accessible ΔG‡ barrier. Our computational results, which are in consonance with the kinetic parameters derived from lumped models, the results of isotopic labeling experiments and the reported HMF/FF molecular ratios, could be useful for modeling studies including on nonequilibrium kinetic effects that may render more information about product yields and the relevance of the various pathways.

Study of authenticity, quality characteristics and bioactivity in honey samples from different botanical origins and countries

Honey is a widely consumed commodity featuring beneficial nutritional properties resulting in a high market price. Therefore, honey is a target of fraudulent practices and analytical strategies to assess honey quality and origin are highly needed. Within this context, we performed a comprehensive analytical testing for 39 honey samples originating from Greece and other countries. Analytical parameters related to honey quality control (Directive 2001/110/EC) were monitored. In detail, hydroxymethylfurfural (HMF) and diastase activity were measured using spectrophotometric assays. Importantly, 6 samples imported by the American market exceeded the regulatory limit (40 mg/kg). The content of the main honey sugars was monitored using an accredited ultra-high-performance liquid chromatography coupled to evaporative light scattering detector (UHPLC-ELSD) and all samples were in line with the regulatory standards. In addition, chromatographic analysis was performed to determine 23 phenolic compounds as these are bioactive compounds contributing towards the health promoting effects of honey. Besides chemical characterisation, in vitro testing was also performed by monitoring the inhibitory effect of the honey samples towards acetylcholinesterase (AChE) and pancreatic lipase (PNLIP). Indeed, inhibition was noticed and in the case of PNLIP the monitored differences between Greek and samples from other countries were statistically significant. To assess honey sample authenticity, chemometric tools were employed, namely, principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA). The multivariate analysis revealed that the taxifolin content may be used as a marker for thyme honey from Cyprus while the total content of gallic and protocatechuic acids could be used as a marker for oak honeys. All in all, implementing several different methods based on different principles (both physicochemical and bioanalytical) in a complex analytical matrix such as honey is a great analytical challenge that we successfully faced and comprehensively demonstrated in this study.

Model-Assisted Optimization of Xylose, Arabinose, Glucose, Mannose, Galactose and Real Hemicellulose Streams Dehydration To (Hydroxymethyl)Furfural and Levulinic Acid.

Conversion of hemicellulose streams and the constituent monosaccharides, xylose, arabinose, glucose, mannose, and galactose, was conducted to produce value-added chemicals, including furfural, hydroxymethylfurfural (HMF), levulinic acid and anhydrosugars. The study aimed at developing a kinetic model relevant for direct post-Organosolv hemicellulose conversion. Monosaccharides served as a tool to in detail describe the kinetic behavior and segregate contribution of hydrothermal decomposition and acid catalyzed dehydration at the temperature range of 120-190 °C. Catalyst free aqueous media demonstrated enhanced formation of furanics, while elevated temperatures led to significant saccharide isomerization. The introduction of sulfuric and formic acids maximized furfural yield and significantly reduced HMF concentration by facilitating its rehydration into levulinic acid (46 mol%). Formic acid additionally substantially enhanced formation of anhydrosaccharides. An excellent correlation between modeled and experimental data enabled process optimization to maximize furanic yield in two distinct hemicellulose streams. Sulfuric acid-containing hemicellulose stream achieved the highest furfural yield after 30 minutes at 238 °C, primarily due to the high Ea for pentose dehydration (150-160 kJ mol-1). Contrarily, formic acid-containing hemicellulose stream enabled maximal furfural yield at more moderate temperature and extended reaction time due to its lower Ea for the same reaction step (115-125 kJ mol-1).

Comparative study of physiochemical properties in Iranian multi-floral honeys: Local vs. commercial varieties

Iran, a leading honey-producing country, faces challenges in honey exports. This study aimed to evaluate the melissopalynological and physicochemical characteristics of local honeys belonging to Iranian flora, and compare them with Iranian commercial honeys. For this purpose, seven local honey samples were collected from Iran's renowned floristic regions, alongside seven commercial multi-floral honeys from a supermarket. Moisture content (MC), total solids (TS), pH, free acidity (FA), ash, electrical conductivity (EC), sugar profile, hydroxymethyl furfural (HMF), diastase number (DN), and proline were assessed. The sugar profile was analyzed by high-performance liquid chromatography with a refractive index detector (HPLC-RID). Pollen analysis classified local honeys as multi-floral. The results revealed that MC, TS, pH, FA, ash, and EC values in both local and commercial samples conformed to approved standards (Codex Alimentarius and European Union). Two local and one commercial sample exclusively satisfied the sucrose standard level. Of the local honeys, two samples complied with HMF standard, while five fulfilled DN criterion, and four had proline values within acceptable ranges. Conversely, HMF (56.32–228.11 mg/kg), DN (3.13–7.22 Schade units/g), and proline (109.84–173.86 mg/kg) levels in all commercial samples failed to meet the standard. A significant correlation was found between ash and EC (r = 0.915, p < 0.01) in local honeys, whereas no strong correlation (r = 0.299) existed in commercial samples. Hierarchical cluster analysis confirmed that Iranian honeys lacked clustering by botanical origin, possibly due to extensive sugar adulteration or thermal treatment. Overall, study findings confirmed the significantly inferior quality of Iranian commercial honeys compared to local varieties, albeit some local samples also exhibited quality concerns. Accordingly, it is recommended that regulatory bodies provide periodic training for beekeepers and establish monitoring programs to enhance honey quality, thereby boosting Iran's share in the global honey export market.

Furandicarboxylic Acid (FDCA): Electrosynthesis and Its Facile Recovery From Polyethylene Furanoate (PEF) via Depolymerization.

Replacing fossil fuels with renewable, bio-based alternatives is inevitable for the modern chemical industry, in line with the 12 principles of green chemistry. 2,5-Furandicarboxylic acid (FDCA) is a promising platform molecule that can be derived from 5-hydroxymethyl furfural (HMF) via sustainable electrochemical oxidation. Herein, we demonstrate TEMPO-mediated electrooxidation of HMF to FDCA in ElectraSyn 2.0 using inexpensive commercially available electrodes: graphite anode and stainless-steel cathode, thereby avoiding the often cumbersome electrode preparation. Key parameters such as concentration of HMF, KOH, and catalyst loading were optimized by experimental design. Under the optimized conditions, using only a low amount of TEMPO (5 mol%), high yield and Faradaic efficiency of 96% were achieved within 2.5 hours. Moreover, since FDCA is a monomer of the bio-based poly(ethylene furanoate), PEF, we aimed to investigate its recovery by depolymerization, which could be of paramount importance in the circular economy of the FDCA. For this, a new polar aprotic solvent, methyl sesamol (MeSesamol), was used, allowing the facile depolymerization of PEF at room temperature with high monomer yields (up to 85%), while the cosolvent MeSesamol was recycled with high efficiency (95-100%) over five reaction cycles.

Caproate production from the mixture of corn straw and food waste via chain elongation with reinforcement of biofilm

As a precursor, caproate is widely used in food and medicine for production of various valuable products. From an environmental point of view, caproate production by anaerobic fermentation is a sustainable way. The cost of caproate could be reduced if the wasted biomass is used as substrate. In this study, the caproate production from corn straw and food waste was investigated. Results showed that the sulfuric acid – enzyme method was the optimum approach for hydrolysis of corn straw, and the corresponding glucose concentration was 24.3 g/L. At the optimum condition, the 5-hydroxymethyl furfural (HMF) was found to be the main inhibitor of the hydrolysate, which exhibited inhibitory effect to ethanol and caproate fermentation. Further analysis showed that the inhibition threshold of HMF to Clostridium kluyveri was 1.2 g/L. The formation of biofilm in the fermentation system was found to be an effective way for improving the robustness of cells to inhibitors. The caproate production of 13.5 g/L was obtained when the ethanol and acetate derived from corn straw and food waste was used as substrates. This study cast an insight that it was a promising way for caproate production from the corn straw and food waste.

Instant Synthesis of 2,5‐Diformylfuran from Concentrated 5‐Hydroxymethylfurfural without Catalyst and Organic Solvent

Abstract5‐Hydroxymethylfurfural (HMF) was transformed into 2,5‐diformylfuran (DFF) with nitric acid as the oxidant. The initial HMF content was as high as 12.5 wt %, and water was the sole solvent. This is an intensely exothermic reaction along with the emission of NO2 gas. A high DFF yield of 83.2 % was achieved if the oxidation ability of nitric acid matched with the requirement of target oxidation reaction while mismatched those of side reactions by regulating the initial concentration of nitric acid (59.5 wt %) and reaction temperature (50–60 °C). The oxidation reaction of HMF, overoxidation of HMF, and skeleton‐cracking reaction of FDCA preferred concentrated HNO3, hot HNO3, and concentrated or hot HNO3, respectively. After liquid‐liquid extraction, filtration, and column chromatography, light‐yellow DFF powders with purity of 92.1 wt % and isolated yield of 40.2 % were obtained and confirmed by NMR, FTIR, UV‐Vis, and elemental analysis. HMF was the dominant impurity due to its affinity to DFF. In addition, chromogenic substances were obtained as a byproduct, and they were potential pH indicators. These chromogenic substances had highly conjugated molecular structures, and they were generated via successive β‐protonation‐based ring‐opening reaction of HMF, aldol reaction, and dehydration reaction.

Single feed droplet–catalyst particle collision in a liquid containing gas–solid fluidized bed to convert fructose to value-added chemicals

Carbohydrates, comprising C6 sugars, dehydrate to form furfural (FUR) and 5- hydroxymethyl furfural (HMF). HMF is an intermediate for value-added specialty chemicals like 2,5-diformyl furan (DFF) and 2,5-furandi carboxylic acid, a monomer for polyethylene furaonate. Atomizing sugar solutions into catalytic fluidized beds operating beyond the caramelization temperature, Tcarm, accelerates reaction rates while avoiding humins, which are color forming agents characteristic of liquid phase processes. However, droplets partially coat particles in the spray zone and agglomerate due to liquid cohesive forces, which reduces heat transfer rates at the micro-scale and degrades reaction rates at the macro-scale. Here, we developed a CFD model to study the collision between a single feed droplet and a catalytic particle above Tcarm. We focused on evaluating the evaporation rate and heat transfer between the droplet and particle to promote vaporization the liquid feed, and assessing the impact of bed temperature, liquid feed rate, and superficial gas velocity. The highest DFF and furfural selectivity obtained are 17% and 24%, respectively, and these values are correlated to the maximum coke formation and agglomeration of 0.6% and 12g. However, the corresponding heat transfer and mass transfer are among the lowest values of 40% and 0.5W.

Influence of Ultrasonication and UV-C Processing on the Functional Characteristics and Anticarcinogenic Activity of Blackthorn Vinegar.

In recent years, consumer trends have been changing toward fresh food products such as fruit juice, vinegar, etc. that are a good source of bioactive components, high nutritional characteristics, and beneficial microorganisms. Blackthorn (Prunus spinosa L.) vinegar (BV) is one of these nutritious foods. The study aims to examine the efficacy of ultraviolet-C (UV-C) light applied by a modified reactor and ultrasonication on bioactive compounds (total phenolic, total flavonoid, ascorbic acid content, and antioxidant activity) of traditionally produced BV. Furthermore, the volatile organic compound (VOC) profile, hydroxymethylfurfural (HMF) content, cytotoxicity properties, and color were assessed. UV-C light and ultrasonication processes enriched most bioactive components, but these methods did not significantly improve ascorbic acid (p > 0.05) compared to pasteurization. Twenty-seven volatile compounds were analyzed in order to determine the VOC profile. As a result, thermal and nonthermal methods were found to affect the profile significantly (p < 0.05). No significant differences were detected in total soluble solids (4.70-4.77), titratable acidity (3.81-3.87), and pH (3.39-3.41) values. The anticarcinogenic activities of UV-C-treated BVs were more significant than others. Nonthermal treatments were generally better than pasteurization in maintaining and enriching the quality of BV. In this study, UV-C light and ultrasonication technology can be used as an alternative to traditional thermal techniques to improve the quality of BV.

Diels-Alder Cycloaddition of 2,5-Bis(hydroxymethyl)furan (BHMF) and N-Phenylmaleimide Derivatives.

Currently, amidst atmospheric menace where natural calamities such as wildfire and floods are becoming more frequent than ever, biobased derivatives offer a sustainable alternative to conventional ways, for instance, petrochemical commodities. Biobased products, obtained from agricultural waste, including 5-(hydroxymethyl)furfural (HMF), 2,5-bis(hydroxymethyl)furan (BHMF), and 2,5-furandicarboxylic acid (FDCA) are promising chemical platforms in the biorefinery, which is yet to be explored. The Diels-Alder cycloaddition of BHMF and N-phenylmaleimide derivatives under optimal reaction conditions is investigated in this report. First, HMF is reduced to BHMF in the presence of NaBH4, and then the Diels-Alder reaction of BHMF and N-phenylmaleimide derivatives is investigated to produce Diels-Alder adducts. All novel compounds are synthesized in acceptable yields and effectively characterized by employing important techniques such as one-dimensional (1D) NMR spectroscopy (1H, 13C, DEPT-90, and DEPT- 135), two-dimensional (2D) NMR spectroscopy (1H-1H COSY, 1H-13C HSQC, and 1H-13C HMBC), IR spectroscopy, elemental analysis, mass spectrum (QTOF), and single-crystal X-ray diffraction (SC-XRD). Furthermore, this study underlines the necessity of sustainable synthetic methodologies and gives critical insights into the progress of ecologically friendly methodologies, providing a new avenue as a tunable precursor for the challenging functionalized polymer in the future.

CO2 Reduction in a Bio Mass-Paired Systems for the Production of e-Chemicals

The electrification of chemical manufacturing is an important pathway toward reduced CO2 emissions. Direct electrochemical CO2 reduction can thereby become a key technology. CO2 electrolyzers produce cathodically platform chemicals as CO, format, ethanol or ethylene. The state-of-the-art anode process is the oxygen electro evolution which suffers from high over potentials and moderate valorization. An alternative is the anodic oxidation of biomass to valorized carbonaceous products, such as the oxidation of hydroxymethylfurfural (HMF) to the biopolymer precursor 2.5-furandicarboxylic acid (FDCA).In this work we report the design of electrolyzers flow cells with paired valorization of biomass and CO2. NiNC cathode GDEs are used for CO2 reduction to CO and NiFe-LDH anodes for the HMF oxidation in a zero-gap membrane electrolyzer flow cells. We used a bipolar membrane to separate and optimize either half-cell reactions. Inside the membrane, water is dissociated and the protons will neutralize carbonates on the cathode which is beneficial for a higher CO2 utilization and single pass. So, we can report close to 95% FE and 100% utilization efficiency towards CO.On the other hand, the hydroxide will stabilize the anode pH and enable PGM-free anodes compared to AEM CO2 electrolyzer. State-of-the-art HMF oxidation is a semi-batch setup, in which the HMF containing anolyte is recycled to complete HMF depletion and utilization. This design suffered from severe mass limitations. Therefore, we modified the semi-batch process into a continuous process and made tradeoffs between faradaic efficiency and utilization. As HMF is not stable in alkaline solutions we decided that a high utilization is beneficial because the intermediates are stable and could be recycled. We can report a single pass conversion of around 70 % towards FDCA at 200 mA cm-2 at a total utilization of 90%.Figure caption: Paired continuous HMF/CO2 electrolyzer with performance parameter. Figure 1

Microbiological and physicochemical characterization of organic and nonorganic honey sold in São Paulo State

This study assesses the microbiological and physicochemical quality of organic and nonorganic honey sold in São Paulo State, Brazil. A total of 26 samples were analyzed, 10 samples of organic honey (OH) and 16 of non-organic honey (NOH) sold in São Paulo State, Brazil. Physicochemical analyses revealed notable variations in moisture, acidity, and hydroxymethylfurfural (HMF) levels between OH and NOH. The average moisture content was 17.74 ± 1.47 g/100 g for OH and 18.12 ± 1.73 g/100 g for NOH. Regarding acidity, OH had an average of 26.90 ± 14.58 mEq/kg, while NOH had 34.32 ± 11.22 mEq/kg. Regarding HMF, OH had an average of 23.40 ± 38.70 mg/kg and NOH had 35.82 ± 39.94 mg/kg. Samples showing deviations from legal standards indicate potential processing or storage issues. The Fiehe test indicated possible fraud in one OH sample and four NOH samples. The Lund test showed no precipitation in any samples, suggesting adulteration in all of them. Diastatic enzyme research revealed the absence of enzymes in three samples, indicating adulteration or inadequate processing. The mean counts of mesophiles were 23 CFU/g for OH and 55.33 CFU/g for NOH, while the counts of molds and yeasts were 126.5 CFU/g for OH and 2289 CFU/g for NOH, exceeding recommended limits and raising concerns about product safety. These findings underscore the need for rigorous quality control measures throughout honey production to ensure safety, purity, and authenticity.

Assessment of 5-Hydroxymethylfurfural in Food Matrix by an Innovative Spectrophotometric Assay.

Foods contaminants pose a challenge for food producers and consumers. Due to its spontaneous formation during heating and storage, hydroxymethylfurfural (HMF) is a prevalent contaminant in foods rich in carbohydrates and proteins. Colorimetric assays, such as the Seliwanoff test, offer a rapid and cost-effective method for HMF quantification but require careful optimization to ensure accuracy. We addressed potential interference in the Seliwanoff assay by systematically evaluating parameters like incubation time, temperature, and resorcinol or hydrochloric acid concentration, as well as the presence of interfering carbohydrates. Samples were analyzed using a UV-Vis spectrophotometer in scan mode, and data obtained were validated using HPLC, which also enabled quantification of unreacted HMF for assessing the protocol's accuracy. Incubation time and hydrochloric acid percentage positively influenced the colorimetric assay, while the opposite effect was observed with the increase in resorcinol concentration. Interference from carbohydrates was eliminated by reducing the acid content in the working reagent. HPLC analyses corroborated the spectrophotometer data and confirmed the efficacy of the proposed method. The average HMF content in balsamic vinegar samples was 1.97 ± 0.94 mg/mL. Spectrophotometric approaches demonstrated to efficiently determine HMF in complex food matrices. The HMF levels detected in balsamic vinegars significantly exceeded the maximum limits established for honey. This finding underscores the urgent need for regulations that restrict contaminant levels in various food products.

Efficient Conversion of Glucose to Hydroxymethylfurfural: One-pot Brønsted Base and Acid Promoted Selective Isomerization and Dehydration.

Development of elegant, selective, and efficient strategies for the production of value-added platform chemicals from renewable feedstocks are in high demand to achieve the future needs and sustainable goals. In this context, an efficient acid-promoted synthesis of highly valuable hydroxymethylfurfural (HMF) has been demonstrated from glucose, a major constituent of lignocellulosic biomass. The major challenge in the conversion of glucose to HMF is the selective isomerization of glucose to ketose, which in the present work has been successfully addressed through the amine-mediated rearrangement of glucose to aminofructose under Amadori rearrangement. Importantly, subsequent dehydration step affords HMF and regenerates the amine employed in the first step, which could be readily recovered. In addition, scale-up and successful integration into one-pot synthesis of HMF proves the efficiency and applicability of the present transformation in large scale application. In addition, the method was also successfully extended to other monosaccharides and disaccharides to produce HMF.

Catalysts for Biomass Upgrading: Transforming 5‐Hydroxymethyl Furfural into 2,5‐Furan Dicarboxylic Acid for Fine Chemicals, Featuring Mil‐100(Fe) Mof as a Novel Catalyst

AbstractThis review underscores the potential of metal‐organic frameworks (MOFs), exemplified by MIL‐100(Fe), as catalysts in the conversion of 5‐Hydroxymethyl Furfural to 2,5‐Furan Dicarboxylic Acid, which is crucial in bioplastics and value‐added chemical production. MOFs exhibit advantages, including recyclability, stability, and catalytic potential under mild conditions. Despite promising results, MOFs in this application are underexplored compared to traditional metal catalysts. Noble metal catalysts (Au, Pt, and Pd) face challenges such as cost and limited recyclability. Mechanistic studies favor the DFF route, highlighting the oxidation of HMF's hydroxyl group as predominant. Molecular oxygen proves effective for HMF to FDCA transformation, with gold‐based catalysts noted for selectivity. Ongoing industrial efforts by companies like Avantium indicate a shift towards sustainable alternatives. This review highlights research gaps concerning the necessity for custom Metal‐Organic Framework (MOF) catalysts in the transformation of hydroxymethylfurfural (HMF) into 2,5‐furandicarboxylic acid (FDCA). The study recommends, among other things, 1) the adoption of base‐free conversion systems, 2) a focus on large‐scale FDCA manufacturing, prioritizing environmental sustainability despite prevailing cost challenges, and 3) fostering multidisciplinary collaboration. Utilizing advanced engineering software, such as ASPEN HYSYS, is proposed for optimizing these processes and paving the way for the successful industrialization of FDCA in the future.

Hydrolysis of Babool wood biomass using carbocation scavengers assisted ionic liquid pretreatment for the production of sugars and furfurals

The present study highlights the performance of carbocation scavengers for the pretreatment of hardwood biomass followed by the production of bio-based products. The behaviour of different carbocation scavengers namely; 2-Napthol, 4 Hydroxybenzoic acid, Vanillic acid, Catechol, Hydroquinone, Resorcinol and Phenol and their mitigating effect on the rate of hydrolysis was explored under different operating conditions. All the carbocation scavengers show significant changes in the crystallinity index leading to distinct morphological and physiochemical changes in the biomass structure. Results revealed that the addition of carbocation scavengers not only reduces the inhibitory effect of structured lignin but also enhances the accessibility of cellulose and hemicellulose and facilitates the production of sugars and 5-Hydroxymethyl Furfural. Maximum 5-HMF yield was observed using 2-Napthol at an optimised concentration of 2 wt% (1.5 mL) at 190 °C in 60 min. Further, to evaluate the effect of acetyl groups, biomass deacetylation was also performed. The highest deacetylation effect was observed at 170 °C and showed ∼73% and ∼94% reduction in the holocellulosic content in 60 min. The proposed study develops a sustainable and viable route to suppress the inhibitory effect of lignin with the utilization of carbocation scavengers and enhances biomass digestibility that favours the production of bio-based chemicals.

Utilization of orange peel waste for sustainable amino acid production by Corynebacterium glutamicum.

Oranges are the most processed fruit in the world-it is therefore apparent that the industrial production of orange juice generates large quantities of orange peel as a by-product. Unfortunately, the management of the orange peel waste leads to economic and environmental problems. Meanwhile, the use of sustainable raw materials for the production of bulk chemicals, such as amino acids, is becoming increasingly attractive. To address both issues, this study focused on the use of orange peel waste as a raw material for media preparation for the production of amino acids by engineered Corynebacterium glutamicum. C. glutamicum grew on pure orange peel hydrolysate (OPH) and growth was enhanced by the addition of a nitrogen source and a pH buffer. Inhibitory effects by the combination of high concentrations of OPH, (NH4)2SO4, and MOPS buffer in the wild-type strain (WT), were overcome in the tyrosine-producing engineered C. glutamicum strain AROM3. Genetic modifications that we identified to allow for improved growth rates under these conditions included the deletions of the vanillin dehydrogenase gene vdh, the ʟ-lactate dehydrogenase gene ldhA and the 19 genes comprising cluster cg2663-cg2686. A growth inhibiting compound present in high concentrations in the OPH is 5-(hydroxymethyl)furfural (HMF). We identified vdh as being primarily responsible for the oxidation of HMF to its acid 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), as the formation of HMFCA was reduced by 97% upon deletion of vdh in C. glutamicum WT. In addition, we showed that growth limitations could be overcome by adjusting the media preparation, using a combination of cheap ammonia water and KOH for pH neutralization after acidic hydrolysis. Overall, we developed a sustainable medium based on orange peel waste for the cultivation of C. glutamicum and demonstrated the successful production of the exemplary amino acids ʟ-arginine, ʟ-lysine, ʟ-serine, ʟ-valine and ʟ-tyrosine.

Rapid analysis of untreated food samples by gel loading tip spray ionization mass spectrometry.

Rapid, efficient, versatile, easy-to-use, and non-expensive analytical approaches are globally demanded for food analysis. Many ambient ionization approaches based on electrospray ionization (ESI) have been developed recently for the rapid molecular characterization of food products. However, those approaches mainly suffer from insufficient signal duration for comprehensive chemical characterization by tandem MS analysis. Here, a commercially available disposable gel loading tip is used as a low-cost emitter for the direct ionization of untreated food samples. The most important advantages of our approach include high stability, and durability of the signal (> 10min), low cost (ca. 0.1 USD per run), low sample and solvent consumption, prevention of tip clogging and discharge, operational simplicity, and potential for automation. Quantitative analysis of sulfapyridine, HMF (hydroxymethylfurfural), and chloramphenicol in real sample shows the limit-of-detection 0.1μgmL-1, 0.005μgmL-1, 0.01μgmL-1; the linearity range 0.1-5μgmL-1, 0.005-0.25μgmL-1, 0.01-1μgmL-1; and the linear fits R2 ≥ 0.980, 0.991, 0.986. Moreover, we show that tip-ESI can also afford sequential molecular ionization of untreated viscous samples, which is difficult to achieve by conventional ESI. We conclude that tip-ESI-MS is a versatile analytical approach for the rapid chemical analysis of untreated food samples.