Conversion Of Monosaccharides Research Articles

Conversion of Monosaccharides into Aromatic Compounds over a Charcoal-supported Platinum Catalyst in High-temperature Water

Conversion of Monosaccharides into Aromatic Compounds over a Charcoal-supported Platinum Catalyst in High-temperature Water

Electrochemical and Non-Electrochemical Pathways in the Electrocatalytic Oxidation of Monosaccharides and Related Sugar Alcohols into Valuable Products.

In this contribution, we review the electrochemical upgrading of saccharides (e.g., glucose) and sugar alcohols (e.g., glycerol) on metal and metal-oxide electrodes by drawing conclusions on common trends and differences between these two important classes of biobased compounds. For this purpose, we critically review the literature on the electrocatalytic oxidation of saccharides and sugar alcohols, seeking trends in the effect of reaction conditions and electrocatalyst design on the selectivity for the oxidation of specific functional groups toward value-added compounds. Importantly, we highlight and discuss the competition between electrochemical and non-electrochemical pathways. This is a crucial and yet often neglected aspect that should be taken into account and optimized for achieving the efficient electrocatalytic conversion of monosaccharides and related sugar alcohols into valuable products, which is a target of growing interest in the context of the electrification of the chemical industry combined with the utilization of renewable feedstock.

Перспективы глубокой переработки бумажного шлама с применением ферментов, микроводорослей и дрожжей

This article presents the information on the valorization of waste generated during the production of tissue paper. The possibility of bioconversion of the polysaccharide part of paper sludge into simple sugars has been evaluated. The options for processing the paper sludge before enzymic hydrolysis to achieve the maximum yield of monosaccharides have been considered. Pretreatment with acids has been found to be a key step before the biocatalytic cleavage of waste polysaccharides. An additional yield of enzymic hydrolysis products after pretreatment with acids has been obtained by pre-extraction of the paper sludge with spirit or acetone. It has been established that the most intense enzymic hydrolysis of readily available fractions of the paper sludge takes place in the first 10–12 hours. Further, the process slows down, probably due to the action of the remaining components of the fillers, as well as an increase in the proportion of the difficult-to-hydrolyze polysaccharide part. In all cases, the proportion of absolutely dry non-hydrolyzed residue has been about 43±2 % of the dry matter of the paper sludge. The main products of enzymic hydrolysis have been glucose and xylose. The resulting sugars have been used for mixotrophic cultivation of the Tetradesmus obliquus and Chlorella vulgaris algae. Yeast strains have been selected for the conversion of monosaccharides from the paper sludge. In a series of experiments on non-sterile yeast cultivation, the Candida utilis PAL D and Debaryomyces hansenii SWING R cultures have turned out to be the most productive (within 2.10±0.14 g of air-dry yeast weight/dm3 per 24 hours). The degree of conversion of hydrolysate sugars has been 70±2 %. Most of the remaining sugars (about 80 %) have been represented by xylose. Complete utilization of the sugars has taken place on the 2nd day when having added an extra nitrogen source to the medium. On the other hand, the spent nutrient medium after yeast separation has been suitable for mixotrophic cultivation of microalgae. It has been revealed that the economic costs of pre-treatment of the paper sludge with nitric acid can be leveled by using the resulting salts as a nitrogen source for cultivating yeast. In doing so, the yield of yeast biomass increases by almost 2 times.

Lignocellulosic biomass pretreatment with a lignin stabilization strategy and valorization toward multipurpose fractionation

Lignocellulosic biomass has emerged as a promising alternative with sustainable advantages for the production of a wide range of renewable products and value-added chemicals. In this study, a pretreatment strategy that use a fully recyclable acid hydrotrope (p-TsOH aqueous solution) to extract lignin and employ glyoxylic acid (GA) to stabilize lignin was proposed for biomass valorization toward multipurpose fractionation. 83.0 % of lignin was dissolved out by p-TsOH hydrotrope (80 wt%) with GA addition to form GA-stabilized product at 80 o C for 15 min. The stabilized lignin was subsequently used as an additive in the preparation of lignin-based suncream. Notably, the incorporation of 4 wt% lignin nanospheres into an SPF15 sunscreen yielded a measured SPF of 59.94. Furthermore, the depolymerization of uncondensed lignin into aromatic monomers yielded a high lignin-oil yield of 84.2 %. Additionally, direct heating of the pretreatment liquor facilitated the conversion of monosaccharides into furfural, achieving a desired yield of 53.7 % without the addition of any acid catalyst. The pretreatment also enhanced the enzymatic hydrolysis of glucan, resulting in a saccharification yield of 98.4 %. Moreover, short-term ultrasonication of the pretreated substrate yielded pulp suitable for papermaking. Incorporating 15 wt% fibers into the produced paper sheets led to a 5.3 % increase in tear index and a 25.4 % increase in tensile index. This study presents a viable pretreatment strategy for the multipurpose fractionation of lignocellulosic biomass, offering potential avenues for biomass valorization.

Efficient conversion of carbohydrates into 5‐hydroxymethylfurfural using choline chloride-based deep eutectic solvents

In this study, the conversion of monosaccharides to 5-hydroxymethylfurfural (5-HMF) using different deep eutectic solvents (DESs) was investigated in various conditions. Among all the investigated DESs, [ChCl][trichloroacetic acid], based on choline chloride and trichloroacetic acid with the ratio 1:1, showed the highest catalytic activity. A maximum 5-HMF yield was 82 % for 1 h at 100 °C using [ChCl][trichloroacetic acid] as a catalyst from fructose. [ChCl][trichloroacetic acid] could be recovered and reused three times with a slight loss in activity. Our work demonstrated the low-cost and effective method for the synthesis of 5-HMF from carbohydrates.

Efficient synthesis of 5-hydroxymethylfurfural from carbohydrates via SO3H-containing dendrimer β zeolite catalyst

A three-generation dendrimer β zeolite catalyst (G3-β-SO3H) was prepared by successfully growing a triazine dendrimer with a terminal sulfonic acid group on β zeolite surface via a thiol-ene click reaction, which can be used as a bifunctional catalyst for the efficient conversion of carbohydrates to 5-hydroxymethylfurfural (HMF). The composition, structure, microscopic morphology and acidic sites of the G3-β-SO3H zeolite were investigated by elemental analysis, EDS-Mapping, FTIR, XPS, SEM, XRD, N2 adsorption–desorption isotherm, Py-FTIR and NH3-TPD. The catalytic performance of the catalyst was evaluated for the synthesis of HMF by converting carbohydrates in the H2O(NaCl)/tetrahydrofuran (THF) biphasic system. The G3-β-SO3H zeolite catalyst gave remarkable HMF yields for the conversion of monosaccharides, disaccharides, polysaccharides, plant fibrous feedstock (moso bamboo), and waste biomass (wheat straw). By optimizing the reaction conditions, the catalyst achieved a maximum yield of 63.6% HMF from cellulose in H2O(NaCl)/THF system. Further, the catalytic system still resulted in 44% HMF yield from cellulose after five cycles, with acidic site leaching being the main factor in the decrease of the catalyst activity.

Solar-light-driven photocatalytic conversion of monosaccharide by oxygen-doped graphitic carbon nitride/artificial steel converter slag composite

The development of high performance, low-cost and resource-efficient photocatalysts with improved solar light harvesting capabilities can significantly enhance the practicability and viability of photocatalytic conversion of biomass-based substances to value-added chemicals. This work reports the construction of heterojunction between oxygen-doped graphitic carbon nitride and artificial steel converter slag (OCN/artCS) as efficient photocatalysts for conversion of biomass-derived monosaccharide to lactic acid under the simulated solar light. The OCN/artCS composites were facilely fabricated by the thermal polymerization of the mixtures of dicyanamide (DA) and oxalic acid (OA), which are precursors of OCN. The artCS acts as photocatalyst support for OCN to grow on its surface and can provide Ca2Fe2O5 semiconductor to possibly form the OCN/Ca2Fe2O5-containing artCS heterojunction. Compared with pristine OCN, the OCN/artCS composites exhibited higher photocatalytic performance for selective production of lactic acid, possibly due to the effective separation of photogenerated charge carriers after creation of OCN/artCS heterojunction. At the optimal content of artCS in the composites, the OCN/5%artCS delivered 99% glucose conversion and 90% lactic acid yield within 60 min at 50 °C under the simulated sunlight irradiation. This work can be a platform for the efficient utilization of industrial solid wastes for production of high-performance photocatalysts, enabling their promising applications in photobiorefinery and other photocatalytic processes.

Efficient synthesis of sugar alcohols using a composite trimetallic Pt–Ni–Sn/MWCNTs catalyst based on metal element coordination and valence regulation

Functional sugar alcohols are a kind of burgeoning food additives to substitute saccharose due to the prominent biofunctions including moderate sweetness, low calorific values and no influence on blood sugar fluctuation, thus applied widely in food, medical, health protection as well as chemical production. Traditional synthesis of functional sugar alcohols required high temperature and H2 pressure, as well as leading to low reaction efficiency, side reactions and leaching of toxic metal ions. In the present work, Pt–Ni–Sn/MWCNTs catalyst was obtained using a liquid phase reduction method with the transition metals loading of Pt 3.4%, Ni 0.7%, Sn 0.4%, respectively. The catalyst catalyzed the preparation of xylitol, sorbitol, mannitol and galactitol with the high monosaccharide conversion (>99.5%) and yield (>99.1%) under relatively mild conditions (100 °C, 3.0 MPa H2), which were lower than ever reported. For the 13-batch reuse of Pt–Ni–Sn/MWCNTs, the total conversion of xylose was 99.4% and the total yield of xylitol was 99.2%, the productivity of 103.2 g xylitol per gram of catalyst was also obtained. Besides, no side reactions, no metal ions as well as no changes of pH were observed in the reaction process. Our trimetallic catalyst exhibited valuable potential in functional sugar alcohols production.

Synthesis of Hollow Mesoporous Silica Nanospheroids with O/W Emulsion and Al(III) Incorporation and Its Catalytic Activity for the Synthesis of 5-HMF from Carbohydrates

Controlling the particle size as well as porosity and shape of silica nanoparticles is always a big challenge while tuning their properties. Here, we designed a cost-effective, novel, green synthetic method for the preparation of perforated hollow mesoporous silica nanoparticles (PHMS-1) using a very minute amount of cationic surfactant in o/w-type (castor oil in water) emulsion at room temperature. The grafting of Al(III) through post-synthetic modification onto this silica framework (PHMS-2, Si/Al ~20 atomic percentage) makes this a very efficient solid acid catalyst for the conversion of monosaccharides to 5-HMF. Brunauer–Emmett–Teller (BET) surface area for the pure silica and Al-doped mesoporous silica nanoparticles (MSNs) were found to be 866 and 660 m2g−1, respectively. Powder XRD, BET and TEM images confirm the mesoporosity of these materials. Again, the perforated hollow morphology was investigated using scanning electron microscopic analysis. Al-doped hollow MSNs were tested for acid catalytic-biomass conversion reactions. Our results show that PHMS-2 has much higher catalytic efficiency than contemporary aluminosilicate frameworks (83.7% of 5-HMF yield in 25 min at 160 °C for fructose under microwave irradiation).

Degradation of cellulose polymorphs into glucose by HCl gas with simultaneous suppression of oxidative discoloration

As cellulose is the main polysaccharide in biomass, its degradation into glucose is a major undertaking in research concerning biofuels and bio-based platform chemicals. Here, we show that pressurized HCl gas is able to efficiently hydrolyze fibers of different crystalline forms (polymorphs) of cellulose when the water content of the fibers is increased to 30–50 wt%. Simultaneously, the harmful formation of strongly chromophoric humins can be suppressed by a simple addition of chlorite into the reaction system. 50–70 % glucose yields were obtained from cellulose I and II polymorphs while >90 % monosaccharide conversion was acquired from cellulose IIIII after a mild post-hydrolysis step. Purification of the products is relatively unproblematic from a gas-solid mixture, and a gaseous catalyst is easier to recycle than the aqueous counterpart. The results lay down a basis for future practical solutions in cellulose hydrolysis where side reactions are controlled, conversion rates are efficient, and the recovery of products and reagents is effortless.

Multienzymatic conversion of monosaccharides from birch biomass after pretreatment

This study presents proof-of-concept validation of a multi enzymatic biocatalytic system, capable of producing monosaccharides from a birch biomass pretreated liquor with simultaneous cofactor regeneration. To improve the stability of the proposed biocatalyst, co-immobilization of NAD + -dependent xylose dehydrogenases, glucose dehydrogenase, and NADH-dependent 3-hydroxybutyrate dehydrogenase was performed on mesoporous silica SBA-15. The results of the physicochemical analysis confirmed the effectiveness of enzymes deposition on the support material and changes in the surface area and porous structure of silica before and after the process. Process conditions in which the three-enzymes system allowed to achieve the highest efficiency of the conducted reactions were optimized at 20 °C, pH 7, 90 min of process duration, 400 mM of levulinic acid addition and ratio of NAD + :NADH 1:5. Results from this study demonstrate excellent xylonic acid, gluconic acid and 4-hydroxyvaleric acid production at conversion rate of 98.7%, 95.6% and 99.2%, respectively. In addition, the high stability and reusability of the developed biocatalytic system was confirmed based on tests in ten successive catalytic cycles and the storage time of 10 days at 4 °C. At the end of the tests, co-immobilized enzymes were capable of catalyzing the process with >70% efficiency. The presented data confirmed the effectiveness of co-immobilization, improvement of enzyme properties including their high reusability, as well as indicated the application potential of the proposed multienzymatic system in the conversion of components of pretreated biomass solutions. • Three types of dehydrogenases have been successfully co-immobilized using silica SBA-15. • Monosaccharides from the birch biomass pretreated liquor were effectively converted. • Addition of levulinic acid ensured the creation of a cofactor regeneration system. • The production of three organic acids was carried out with over 95% of efficiency. • Co-immobilized enzymes retained 70% of acids productivity after 10 catalytic cycles.

Ni-Fe alloying enhances the efficiency of the maltose hydrogenation process: The role of surface species and kinetic study

Unlike the conversion of monosaccharides to the corresponding polyols, the production of maltitol by hydrogenation of maltose has been seldom investigated in the literature, despite its industrial importance. Monometallic Ni catalysts are known for their lack of stability, and the objective of the present paper is to determine through a kinetic study, to what extent a Ni-Fe/SiO2 bimetallic catalyst would outperform a Ni/SiO2 catalyst in the aqueous phase hydrogenation of maltose, as they have been reported to do for monosaccharides. The effect of reaction parameters (T = 80–150 °C, PH2 = 20–40 bar, maltose mass fraction in water = 4.4–17.5 wt%) on activity, selectivity, and stability was examined. In all cases, maltitol was the major product, with a carbon balance higher than 98%, but maltose hydrolysis to glucose occurred in the upper range of temperature. In order to preserve both the catalyst selectivity and stability, a temperature of 80 °C was selected for the kinetic study. A first order model including an inhibiting term based on maltose concentration could fit the evolution of the conversion of maltose as a function of time. The adsorption constant of maltose and the apparent hydrogenation rate constant for the Ni-Fe catalyst were both larger by a factor 2–3 compared with the Ni catalyst, indicating a stronger interaction of maltose with the Ni-Fe surface. Another major difference was a reaction order of 0.5 with respect to the hydrogen pressure on Ni-Fe/SiO2 compared with a near zero-order on Ni/SiO2, stressing significant differences in coverage of the bimetallic surface. The activity of the Ni-Fe catalyst remained constant for three runs of reaction without major structural changes, while the Ni catalyst deactivated by transforming to a phyllosilicate phase. As far as activity, selectivity and stability are concerned; Ni-Fe/SiO2 appeared as a better suited catalyst than Ni/SiO2 for the aqueous phase hydrogenation of maltose at 80 °C, with a more pronounced benefit than formerly reported for xylose on the same catalysts.

Aqueous conversion of monosaccharides to furans: were we wrong all along to use catalysts?

Dehydration of the most relevant biomass derived monosaccharides, xylose, glucose and fructose, was investigated to attain value-added platform chemicals: furfural, hydroxymethylfurfural (5-HMF) and levulinic acid (LA).

Production of 5-Hydroxymethylfurfural from glucose using Al2O3-TiO2-ZrO2 ternary catalysts

In this work, mixed oxides Al2O3-TiO2-ZrO2 were evaluated varying their composition (% w/w) for the conversion of monosaccharides (fructose and glucose) to 5-hydroxymethylfural (HMF). Materials were characterized using Thermogravimetric Analysis and Differential Scanning Calorimetry (TGA-DSC), Nitrogen Physisorption (N2), X-ray Diffraction (XRD), RAMAN Spectroscopy, DRS UV-Vis Spectroscopy, Infrared Spectroscopy (FTIR), SEM, TEM, FTIR-Pyridine and Temperature Programmed Desorption of CO2 (TPD-CO2). The reactions were carried out at 175 °C and 30 bar of Ar pressure in a biphasic system (THF/H2O) for 3 h, obtaining a 78% maximum yield of HMF from the glucose and 63% yield from fructose. The materials studied carried out a direct dehydration of the monosaccharides to HMF in 30 min of reaction and were obtained as intermediates to dehydrate levulinic acid (LA) and formic acid (FA), these intermediates were analyzed and eluted using 1H NMR technique.

INFLUENCE OF ULTRA LOW AND HIGH TEMPERATURE ON ENZYMATIC PRETREATMENT OF BEECH BRANCHES WOOD

The publication is focused on the effect of ultra low and high temperature on enzymatic pretreatment of beech wood (Fagus sylvaticaL.). Two fractions < 0.7 mm and 1.0 –2.5 mm of disintegrated branches sawdust were used for experiments. Glucose and xylose yields were measured after 24, 48, and 72 hours of enzymatic hydrolysis with 15 % load of the enzyme measured to total cellulose content. The influence of freezing under -80°C and boiling under pressure at +160°C on samples before enzymatic hydrolysis was observed. Mutual combination of boiling under pressure to obtain the maximum water uptake and subsequent freezing was used to better understand the process of cell destruction. The results show that the boiling pretreatment has a positive influence on thetotal monosaccharide yields and the subsequent freezing may slightly increase these yields even further. The maximum monosaccharide conversion (73.24%) was achieved using the fraction < 0.7 mm.

Preparation of a bagasse-based solid catalyst loaded with phosphotungstic acid and its catalytic activity in the conversion of monosaccharide

Preparation of a bagasse-based solid catalyst loaded with phosphotungstic acid and its catalytic activity in the conversion of monosaccharide

Influence of Lewis and Brønsted acidic sites on graphitic carbon nitride catalyst for aqueous phase conversion of biomass derived monosaccharides to 5-hydroxymethylfurfural

Conversion of saccharides to 5-hydroxymethylfurfural is one of the fundamental steps in the synthesis of biodiesel. In this work, we report on the influence of Lewis and Brønsted acidic sites on metal-free graphitic carbon nitride catalysts for the conversion of monosaccharides to 5-hydroxymethylfurfural. We have examined the Lewis acidic sites by doping boron onto graphitic carbon nitride, and under optimal conditions, a maximal 91% yield of 5-hydroxymethylfurfural has been obtained from fructose. Subsequently, the boron doped graphitic carbon nitride was functionalized with Brønsted acidic group to prepare sulfonic acid functionalized boron doped graphitic carbon nitride, which possesses both Lewis and Brønsted acidic sites. However, the use of sulfonic acid functionalized boron doped graphitic carbon nitride as catalyst resulted in a lower yield (78%) of 5-hydroxymethylfurfural from fructose. In addition, time-dependent nuclear magnetic resonance spectroscopic study, temperature-programmed desorption study, and green metrics calculations have been performed to substantiate our findings. Overall, this work provides valuable insights on the influence of Lewis and Brønsted acidic sites on graphitic carbon nitride for biomass conversion reactions.

Utilization of enzymatic hydrolysate from corn stover as a precursor to synthesize an eco-friendly adhesive for plywood II: investigation of appropriate manufacturing conditions, curing behavior, and adhesion mechanism

In this study, further research on an enzymatic hydrolysate-ammonium dihydrogen phosphate (EHADP) adhesive was carried out. Appropriate hot pressing conditions were clarified by measuring the bond strength of three-ply plywood bonded with EHADP adhesive, and the results indicated that the appropriate fabricate conditions were 170 °C and 5 min. The value of wet shear strength fulfilled the requirements of China National Standard GB/T 9846–2015 when plywood was fabricated by the appropriate conditions. In the research of curing behavior, the insoluble mass proportion promoted significantly as heating temperature and time were ≥ 170 °C and 5 min. Furthermore, a pyrolysis gas chromatography/mass spectrometry analysis indicated that adding ammonium dihydrogen phosphate (ADP) catalyzed the conversion of monosaccharides in the EHADP adhesive. The adhesion mechanism of the EHADP adhesive was studied by Fourier transform-infrared spectroscopy analysis, and the chemical changes indicated that the adhesion mechanism was attributed to both mechanical and chemical bonding between the wood elements and the cured EHADP adhesive.

Functional and structural characterization of a novel L-fucose mutarotase involved in non-phosphorylative pathway of L-fucose metabolism

Mutarotases catalyze the α-β anomeric conversion of monosaccharide, and play a key role in utilizing sugar as enzymes involved in sugar metabolism have specificity for the α- or β-anomer. In spite of the sequential similarity to l-rhamnose mutarotase protein superfamily (COG3254: RhaM), the ACAV_RS08160 gene in Acidovorax avenae ATCC 19860 (AaFucM) is located in a gene cluster related to non-phosphorylative l-fucose and l-galactose metabolism, and transcriptionally induced by these carbon sources; therefore, the physiological role remains unclear. Here, we report that AaFucM possesses mutarotation activity only toward l-fucose by saturation difference (SD) NMR experiments. Moreover, we determined the crystal structures of AaFucM in the apo form and in the l-fucose-bound form at resolutions of 2.21 and 1.75 Å, respectively. The overall structural folding was clearly similar to the RhaM members, differed from the known l-fucose mutarotase (COG4154: FucU), strongly indicating their convergent evolution. The structure-based mutational analyses suggest that Tyr18 is important for catalytic action, and that Gln87 and Trp99 are involved in the l-fucose-specific recognition.

Application of mannitol producing Leuconostoc citreum TR116 to reduce sugar content of barley, oat and wheat malt-based worts

Achieving a high monosaccharide composition in malt wort is instrumental to achieve successful lactic acid bacteria fermentation of malt based beverages. The conversion of monosaccharides to alternative metabolites such as the sweet polyol, mannitol with heterofermentative strains presents a novel approach for sugar reduction and to compensate for the loss of sweetness. This work outlines the application of an adopted mashing regimen with the addition of exogenous enzymes to produce wort with high fructose content which can be applied to different malted grain types with consistently efficacious monosaccharide production for bacterial fermentation. The so produced worts are then fermented with Leuconostoc citreum TR116 a mannitol hyper-producer. Malted barley, oat and wheat were mashed to stimulate protein degradation and release of free amino acids along with the enzymatic conversion of starch to fermentable sugars. Amyloglucosidase and glucose isomerase treatment converted di- and oligo-saccharides to glucose and provided a moderate fructose concentration in malt worts which was consistent across the three cereals. Fructose was completely depleted during fermentation with Lc. Citreum TR116 and converted to mannitol with high efficiency (>90%) while overall sugar reduction was >25% in all malt worts. Differences in amino acid composition of malt worts did not significantly affect growth of Lc. Citreum TR116 but did affect the formation of the aroma compounds diacetyl and isoamyl alcohol. Organic acid production and acidification of wort was similar across cereal substrates and acetic acid formation was linked to yield of mannitol. The results suggest that differences in amino acid and fructose content of malt worts considerably change metabolite formation during fermentation with Lc. Citreum TR116, a mannitol hyper-producer. This work gives new insight into the development of consumer acceptable malt based beverages which will provide further options for the health conscious and diabetic consumer, an important step in the age of sugar overconsumption.