Separation Of Monosaccharides Research Articles

Thermodynamic and Kinetic Equilibrium for Adsorption of Cellulosic Xylose of Commercial Cation-Exchange Resins.

The development of low-cost purification technology is an indispensable need for industrial biorefinery. Xylose is easily obtained from hydrothermal pretreatment of lignocellulosic biomass. This current study emphasizes the chromatographic monosaccharide separation process using commercial cation-exchange resins (CER) including Amberlite 120 and Indion 225 to separate xylose from a mixture of hydrolysates. To understand the performance of the two CER, the studies of equilibrium, thermodynamics, and kinetics were evaluated. In this study, with different xylose concentrations, the adsorption equilibrium was found to follow the Freundlich isotherm model well (R2 > 0.90 for both CER). The results indicated that a pseudo-second-order model represented the xylose adsorption kinetics. In addition, the activation energy of xylose adsorption onto both CER, i.e., Amberlite 120 and Indion 225 was 34.9 and 87.1 kJ/mol, respectively. The present adsorption studies revealed the potential of these commercial CER to be employed as effective adsorbents for monosaccharide separation technology.

Targeted modification of polyamide nanofiltration membrane for efficient separation of monosaccharides and monovalent salt

Separation of monosaccharides and monovalent salts is important in the biorefinery and food industry. Nanofiltration (NF) technology is promising for this purpose but its poor selectivity still needs to be addressed. In this work, the separation of monosaccharides and monovalent salts by NF is improved by regulating the surface charge and pore size distribution of polyamide NF membranes. The carboxyl groups on the polyamide membrane are selectively activated by N-(3-Dimethylaminopropyl)-N′-ethyl carbodiimide (EDC) and N-hydroxy succinimide (NHS), and subsequently molecules with amino groups are grafted on the membrane to reduce the effective pore size and electronegativity. The conditions and grafted molecules are optimized, and polyethyleneimine (600 Da) is selected as the best for enhancing the separation of glucose/fructose and KCl. Such targeted modification is found to reduce the effective mean pore size while maintaining the porosity of the NF270 membrane, due to pore segmentation. This results in a remarkable improvement in glucose/fructose rejection (from 67.96% to 84.14%) and separation factor (from 2.20 to 6.78), with only a 4.70% permeability loss. The modified membrane also maintains separation performance in crossflow filtration and after alkaline cleaning (pH 12), which outperforms the pristine NF270 and those modified by mussel-inspired coating and simple physical adsorption.

Separation of Fructose and Glucose via Nanofiltration in Presence of Fructooligosaccharides.

Fructose and glucose are commonly present together in mixtures and may need to be separated. Current separation methods for these isomers are complex and costly. Nanofiltration is a cost-effective method that has been widely used for separating carbohydrates of different sizes; however, it is not commonly used for such similar molecules. Here, we report the separation of fructose and glucose in a nanofiltration system in the presence of fructooligosaccharides (FOS). Experiments were performed using a pilot-scale filtration setup using a spiral wound nanofiltration membrane with molecular weight cutoff of 1 kDa. We observed three important factors that affected the separation: (1) separation of monosaccharides only occurred in the presence of FOS and became more effective when FOS dominated the solution; (2) better separation was achieved when the monosaccharides were mainly fructose; and (3) the presence of salt improved the separation only moderately. The rejection ratio (Rf/Rg) in a fructose/glucose mixture is 0.92. We reported a rejection ratio of 0.69, which was observed in a mixture of 50 g/L FOS with a fructose to glucose ratio of 4.43. The separation is hypothesized to occur due to selective transport in the FOS layer, resulting in a preferential binding towards fructose.

Separation of monosaccharides from pretreatment inhibitors by nanofiltration in lignocellulosic hydrolysate: Fouling mitigation by activated carbon adsorption

Lignocellulose pretreatment results in production of hydrolysate consisting of sugars and inhibitors. Previous reports have shown the viability of nanofiltration (NF) of lignocellulosic hydrolysate for simultaneous sugar concentration and inhibitors removal. However, the complexity of real hydrolysate results in severe membrane fouling which greatly hinders the further application of NF in treating biomass hydrolysate. In this investigation, conditioning of real rice straw hydrolysate from dilute acid pretreatment was conducted by three methods (sedimentation, microfiltration (MF) and activated carbon (AC) adsorption) in order to reduce subsequent NF membrane fouling. Results showed that the turbidity, suspended substance (SS) and particle size of SS of the hydrolysate considerably decreased after these three conditioning methods. Only AC adsorption, however, exhibited best performance in terms of increasing the volume reduction ratio (VRR) and decreasing the membrane fouling during NF filtration of rice straw hydrolysate, demonstrating the effectiveness of AC adsorption for hydrolysate conditioning. Further experiments confirmed that removal of phenolics and pigments, the two dominating foulants during NF process, by AC adsorption were most likely responsible for its superior performance compared to sedimentation and MF.

DETERMINATION OF SIMPLE SUGARS IN MEDICINAL PLANT MATERIALS BY THE METHOD OF HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHY (FOR EXAMPLE, THE FRUITS OF SEA BUCKTHORN L. AND NETTLE LEAVES L.)

An analysis of the literature over the past 20 years has shown that when controlling the quality of drugs containing monosaccharides, as well as studying the composition of simple sugars in polysaccharide complexes of medicinal plants and not only, preference is given to physicochemical methods, as the most express, sensitive and informative. No means have been found in the scientific literature to identify and quantify simultaneously various monosaccharides by high performance thin layer chromatography (HPTLC). An economical and rapid method has been developed for the identification and quantitative determination of simple reducing sugars (by the example of glucose, rhamnose and xylose) by the HPTLC method. The optimal conditions for their chromatography in a thin layer of sorbent with a quantitative interpretation of HPTLC data on a personal computer were experimentally selected and theoretically substantiated. In a detailed study of the influence of the polarity of the system on the value of Rf, the intervals of values of the polarity of the eluent were chosen, in which these dependences become linear. Using the proposed dependencies, you can select different systems for the separation of monosaccharides in a thin layer of sorbent, so that the value of Rf fit into the optimal values. The proposed method was tested on medicinal plant raw materials of nettle dioica and sea buckthorn fruits of various conservation methods. Zones of simple sugars of characteristic color were found on the chromatograms of extracts from the studied raw materials, among which glucose, xylose and rhamnose were identified by the characteristic value of Rf values in comparison with reliable standard samples. The technique can be used in quality control of substances, single-component and complex preparations, plant objects, dietary supplements, premixes and products of the food industry.

Direct separation of acetate and furfural from xylose by nanofiltration of birch pretreated liquor: Effect of process conditions and separation mechanism

Lignocellulosic biomass from wood is a potentially rich source of glucose and xylose, which may be used either directly as monosaccharides or function as monomeric building blocks for a range of bioeconomy processes. In this paper we present a forthright separation of monosaccharides from other compounds present in the liquor after thermal biomass pretreatment. The main focus is on separation of xylose from acetate, formate and furans (hydroxymethyl furfural and furfural) by direct nanofiltration of sulphuric acid-hydrothermally pretreated birch liquor (a process optimized for xylose liberation from the biomass). In the study, the performance of eight commercially available flat-sheet membranes with different molecular weight cut-off was compared at 20 and 40 bars of pressure for efficient separation, focusing mainly on xylose retention. The nanofiltration membranes type TS40 (polypiperazine amide) and NF90 (polyamide) with cut-off of around 200 Da were found to be the most suitable for such direct detoxification of the liquor providing xylose retention over 98% and less than 20% retention of the accompanying thermal carbohydrate degradation compounds. The fouling mechanism during separation of the pretreated birch liquor appeared to be mainly cake-layer fouling on the surface of the membrane. Employment of diananofiltration resulted in particularly high purity (over 90%) and recovery (over 99%) of xylose after three diafiltration rounds. Moreover, the selected membranes exhibited great reusability, as the retention of monosaccharides was almost unaltered after five repeated nanofiltration cycles. The data provide new insight into the factors and mechanisms affecting membrane-separation of complex biomass liquors and are of significance for refining of lignocellulosic biomass.

Model-based selection of the degree of cross-linking of cation exchanger resins for an optimised separation of monosaccharides

One of the main steps in designing preparative chromatographic separation units is the selection of a well-performing adsorbent. This is often based on expert knowledge or based on case studies of preselected adsorbents. Therefore, the selection is usually limited in terms of an optimised choice. In this contribution, a model-based optimisation of the selection of an adsorbent on the basis of correlations between structural adsorbent properties with model parameters of a transport dispersive model is proposed. Model parameters of glucose and xylose for five cation exchanger resins with varying degree of cross-linking are experimentally determined in a sequential approach. Void fractions and particle porosities were determined by pulse experiments with different tracers. Single-component isotherms were determined threefold via breakthrough curves with concentrations of up to 250 g l−1 at 60 °C. Mass transfer coefficients were determined by batch experiments. Correlations between the degree of cross-linking of the resins and the Henry coefficients as well as the mass transfer coefficients were derived and applied in an optimisation case study. Based on the derived mathematical formula, the process performance of experimentally not investigated resins were predicted. Further, the selection of a resin for a preparative monosaccharide separation was included into optimisation algorithms.

Insights into the nanofiltration separation mechanism of monosaccharides by molecular dynamics simulation

Abstract Molecular dynamics simulation has been widely used in the membrane separation techniques. In order to further reveal the mechanism of nanofiltration separation of monosaccharides, molecular dynamics method was used to simulate the diffusion process of eight monosaccharides in the aromatic polyamide nanofiltration membrane. Furthermore, the interaction energy between membrane material and monosaccharides was also investigated. Simulation results showed that the interaction force between monosaccharides and membrane material was in the order of sorbose > fructose > glucose > mannose > galactose, and ribose > xylose > arabinose. The diffusion coefficient of eight monosaccharides inside the membrane was in the order of sorbose > galactose > glucose > mannose > fructose > ribose > xylose > arabinose. Within the same experimental conditions, the rejection rate sequences of eight monosaccharides were in the order of: fructose > mannose > glucose > galactose > sorbose > arabinose > xylose > ribose. This finding indicated that solute radius has a clear effect on solute retention. The diffusion ability of solute molecules and the interaction with membrane material also influence the separation of monosaccharides through nanofiltration. A strong interaction force outside the membrane enables many monosaccharide molecules to be adsorbed in the surface of membrane and then driven into the membrane pores which can contribute to the reduction of rejection. Rejection rates were negatively related to the diffusion coefficient of monosaccharides inside the membrane. Monosaccharides can easily pass through the membrane pores under high diffusion ability, thus leading to low rejection rates of monosaccharides.

Recent advances in capillary electrophoresis separation of monosaccharides, oligosaccharides, and polysaccharides

This article illustrates the basis and applications of methodologies for the analysis of simple and complex carbohydrates by means of CE. After a description of the most common and novel approaches useful for the analysis and characterization of carbohydrates, this review covers the recent advances in CE separation of monosaccharides, oligosaccharides, and polysaccharides. Various CE techniques are also illustrated for the study of carbohydrates derived from complex glyco-derivatives such as glycoproteins and glycolipids, essential for biopharmaceutical and glycoproteomics applications as well as for biomarker detection. Most glycans have no significant UV absorption, and derivatization with fluorophore groups prior to separation usually results in higher sensitivity and an improved electrophoretic profile. We also discuss the recent applications and separations by CE of derivatized simple and more complex carbohydrates with different chromophoric active tags. Overall, this review aims to give an overview of the most recent state-of-the-art techniques used in carbohydrate analysis by CE.

Centrifugal partition chromatography in a biorefinery context: Optimisation and scale-up of monosaccharide fractionation from hydrolysed sugar beet pulp

The isolation of component sugars from biomass represents an important step in the bioprocessing of sustainable feedstocks such as sugar beet pulp. Centrifugal partition chromatography (CPC) is used here, as an alternative to multiple resin chromatography steps, to fractionate component monosaccharides from crude hydrolysed sugar beet pulp pectin. CPC separation of samples, prepared in the stationary phase, was carried out using an ethanol: ammonium sulphate (300gL−1) phase system (0.8:1.8v:v) in ascending mode. This enabled removal of crude feedstream impurities and separation of monosaccharides into three fractions (l-rhamnose, l-arabinose and d-galactose, and d-galacturonic acid) in a single step. Throughput was improved three-fold by increasing sample injection volume, from 4 to 16% of column volume, with similar separation performance maintained in all cases. Extrusion of the final galacturonic acid fraction increased the eluted solute concentration, reduced the total separation time by 24% and removed the need for further column regeneration. Reproducibility of the separation after extrusion was validated by using multiple stacked injections. Scale-up was performed linearly from a semi-preparative 250mL column to a preparative 950mL column with a scale-up ratio of 3.8 applied to mobile phase flow rate and sample injection volume. Throughputs of 9.4gL−1h−1 of total dissolved solids were achieved at the preparative scale with a throughput of 1.9gL−1h−1 of component monosaccharides. These results demonstrate the potential of CPC for both impurity removal and target fractionation within biorefinery separations.

Monosaccharide separation from ZnCl2 molten salt hydrates by zeolite beta

Solvent based processes using ionic liquids or molten salt hydrates provide very efficient cellulose dissolution and hydrolysis from lignocellulosic biomass. Efficient separation of sugars from the solvent is very challenging and a hurdle regarding industrial application. Now it is demonstrated that a microporous zeolitic sorbent can provide a very efficient separation of monosugars from a molten salt hydrate containing hydrolysates. Specific details are presented for the separation of glucose from a ZnCl2 molten salt hydrate using Zeolite beta. The molten salt hydrate is promoting the separation in this specific solvent/sorbent combination through a type of salting out adsorption mechanism, leading to a process based on a solvent that allows both efficient cellulose dissolution and hydrolysis and very efficient glucose isolation from the solvent afterwards.

Establishment of a nanofiltration rejection sequence and calculated rejections of available monosaccharides

Abstract To evaluate the feasibility of mixed monosaccharide separation by nanofiltration (NF), a commercial membrane, Desal-5 DK1812, was selected to filter six monosaccharides, including glucose, fructose, mannose, sorbose, arabinose, and xylose. The experiments were performed under the same conditions in single batch of full cycle mode, and the sequence of monosaccharide nanofiltration rejections was obtained. Differences in NF rejections ( R obs ) were analyzed by comparing the molecular structures of the monosaccharides, after which computational molecular sizes ( r s ) were calculated by a mathematical formula correlated with the 3D structures of the molecules. The Donnan steric pore model was used to obtain the rejections ( R cal ) of the monosaccharides as a function of r s . Concentration polarization was also taken into account to calculate R real . The results showed that the r s values of fructose, glucose, mannose, sorbose, arabinose, and xylose were 0.3235, 0.3156, 0.3113, 0.3012, 0.2748, and 0.2677 nm, respectively, and that their R cal agreed well with their R real . Therefore, differences in R obs were mainly due to differences in the molecular structures of the monosaccharides, and calculating r s using molecular structural parameters is reasonable. The results indicated the extreme importance of amplifying rejection differences by regulating computational molecular sizes when separating mixed monosaccharides by NF.

Centrifugal partition chromatography in a biorefinery context: Separation of monosaccharides from hydrolysed sugar beet pulp

A critical step in the bioprocessing of sustainable biomass feedstocks, such as sugar beet pulp (SBP), is the isolation of the component sugars from the hydrolysed polysaccharides. This facilitates their subsequent conversion into higher value chemicals and pharmaceutical intermediates. Separation methodologies such as centrifugal partition chromatography (CPC) offer an alternative to traditional resin-based chromatographic techniques for multicomponent sugar separations. Highly polar two-phase systems containing ethanol and aqueous ammonium sulphate are examined here for the separation of monosaccharides present in hydrolysed SBP pectin: l-rhamnose, l-arabinose, d-galactose and d-galacturonic acid. Dimethyl sulfoxide (DMSO) was selected as an effective phase system modifier improving monosaccharide separation. The best phase system identified was ethanol:DMSO:aqueous ammonium sulphate (300gL−1) (0.8:0.1:1.8, v:v:v) which enabled separation of the SBP monosaccharides by CPC (200mL column) in ascending mode (upper phase as mobile phase) with a mobile phase flow rate of 8mLmin−1. A mixture containing all four monosaccharides (1.08g total sugars) in the proportions found in hydrolysed SBP was separated into three main fractions; a pure l-rhamnose fraction (>90%), a mixed l-arabinose/d-galactose fraction and a pure d-galacturonic acid fraction (>90%). The separation took less than 2h demonstrating that CPC is a promising technique for the separation of these sugars with potential for application within an integrated, whole crop biorefinery.

Separation of monosaccharides hydrolyzed from glycoproteins without the need for derivatization.

Chromatographic separation of monosaccharides hydrolyzed from glycoconjugates or complex, aggregate biomaterials, can be achieved by classic analytical methods without a need for derivatizing the monosaccharide subunits. A simple and sensitive method is presented for characterizing underivatized monosaccharides following hydrolysis from N- and O-linked glycoproteins using high-performance liquid chromatography separation with mass spectrometry detection (LC-MS). This method is adaptable for characterizing anything from purified glycoproteins to mixtures of glycoforms, for relative or absolute quantification applications, and even for the analysis of complex biomaterials. Use of an amide stationary phase with HILIC chromatography is demonstrated to retain the highly polar, underivatized monosaccharides and to resolve stereoisomers and potentially interfering contaminants. This work illustrates an original approach for characterization of N- and O-linked glycoprotein standards, mixtures, and for complex biological materials such as a total yeast extract.

Separation and quantification of microalgal carbohydrates

Structural carbohydrates can constitute a large fraction of the dry weight of algal biomass and thus accurate identification and quantification is important for summative mass closure. Two limitations to the accurate characterization of microalgal carbohydrates are the lack of a robust analytical procedure to hydrolyze polymeric carbohydrates to their respective monomers and the subsequent identification and quantification of those monosaccharides. We address the second limitation, chromatographic separation of monosaccharides, here by identifying optimum conditions for the resolution of a synthetic mixture of 13 microalgae-specific monosaccharides, comprised of 8 neutral, 2 amino sugars, 2 uronic acids and 1 alditol (myo-inositol as an internal standard). The synthetic 13-carbohydrate mix showed incomplete resolution across 11 traditional high performance liquid chromatography (HPLC) methods, but showed improved resolution and accurate quantification using anion exchange chromatography (HPAEC) as well as alditol acetate derivatization followed by gas chromatography (for the neutral- and amino-sugars only). We demonstrate the application of monosaccharide quantification using optimized chromatography conditions after sulfuric acid analytical hydrolysis for three model algae strains and compare the quantification and complexity of monosaccharides in analytical hydrolysates relative to a typical terrestrial feedstock, sugarcane bagasse.

Separation of monosaccharides by solid‐phase extraction with ionic liquid‐modified microporous polymers

Ionic liquid-modified porous polymers with large surface area and large amount of functional groups were developed and used in SPE to separate four monosaccharides. Adsorption isotherm showed that the sorbent with amino ionic liquid groups had the highest interaction with the target compounds. The mobile phase of acetonitrile/water 85:15 and 73:30 v/v can successfully separate the monosaccharides. The sorbent produced reproducible results and performed stably, demonstrating its potential applicability in the separation of extract from natural plant.

Synthesis of Sugar‐Based Silica Gels by Copper‐Catalysed Azide–Alkyne Cycloaddition via a Single‐Step Azido‐Activated Silica Intermediate and the Use of the Gels in Hydrophilic Interaction Chromatography

Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide-alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C-galactoside 1 and propargyl O-lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoids.

Chromatographic Recovery of Monosaccharides for the Production of Bioethanol from Wood

Chromatographic recovery of monosaccharides from concentrated-acid hydrolysates of spruce and birch was investigated for the production of bioethanol from lignocellulose. The effects of resin cross-linkage, column loading, and hydrolysate composition on the yield of monosaccharides and the productivity of the process were of particular interest. Three strong acid cation-exchange resins (gel type) were used. Chromatographic separation experiments were done in a batch column. Monosaccharides were recovered as a “center cut” between sulfuric acid and acetic acid. Hydroxymethyl furfural and furfural, which inhibit the fermentation of monosaccharides, were completely separated from the other components. The highest H2SO4−monosaccharide separation efficiency was obtained with a 6 wt % cross-linked resin. The monosaccharide−acetic acid separation efficiency was found to improve with increasing resin cross-linkage. In the case of high amounts of acetic acid in the hydrolysate, a resin with a high cross-link density is needed for a good yield of monosaccharides. With hydrolysates containing small amounts of acetic acid, a 6 wt % cross-linked resin was found to give the highest yield. The productivity of the process was found to increase with the resin cross-linkage (up to 8 wt %). The optimum column loading depends on whether a high monosaccharide yield or high productivity is desired. The highest yield is obtained with a low loading. As to the productivity, the optimum loading was found to be approximately 10 vol % of the bed volume.

Separation of xylose from glucose by nanofiltration from concentrated monosaccharide solutions

Complex separation of monosaccharides from each other is commercially carried out by chromatographic methods. The possibility of nanofiltration in a demanding separation of a pentose sugar, xylose, from a hexose sugar, glucose, is studied here. Xylose is an intermediate product in xylitol production and glucose interferes in the process. Feed solutions were made of xylose and glucose in different mass ratios and total monosaccharide concentrations. The mass ratios of xylose to glucose in solutions were 1:9, 1:1 and 9:1 and the monosaccharide concentrations of the solutions were 2, 10 and 30 wt.%. Desal-5 DK, -DL and NF270 membranes were used. Filtrations were done in total reflux mode (i.e. both permeate and retentate were recycled back to the feed tank) at 50 °C and the applied pressures were from 2 to 40 bar. The results indicate that the separation of xylose from glucose by nanofiltration is possible to a limited extent. The mass ratio of xylose to glucose in the permeate was 1.5–3.0 times higher than their ratio in the feed. The observed monosaccharide retentions depend highly on permeate flux, and retentions increase to certain reproducible level as pressure and consequently flux is increased. The observed xylose retentions were from 0 to 80% and the glucose retentions were from 10 to 90%. The effect of total monosaccharide concentration on the observed retention is smaller than the effect of flux. The largest difference between xylose and glucose retentions was detected at permeate fluxes between 5 to 30 kg m −2 h −1. The ratio of xylose to glucose in the feed had an influence on permeate flux and on xylose retentions. Xylose retentions decreased as the proportion of glucose increased in the feed. The higher the proportion of xylose in the feed the higher was the total permeate flux.

Conformational separation of monosaccharides of glycoproteins labeled with 2-aminoacrydone using microchip electrophoresis

The conformational separation of monosaccharides labeled with fluorescent 2-aminoacrydone (AMAC) was performed by electrophoresis on a plastic microchip with light-emitting diode confocal fluorescence detection. The AMAC-labeled five neutral monosaccharide mixture (D-glucose (Glc), D-mannose, D-galactose, L-fucose, and D-xylose) or two amino monosaccharide mixture (N-acetyl-D-glucosamine and N-acetyl-D-galactosamine) were well separated at pH 8.5 and 0.5% w/v methylcellulose of 200 mM borate buffer conditions using microchip electrophoresis. The separation was successfully performed considering the difference in stability of the complex between the hydroxyl residue of the monosaccharide and borate ions, and we found that 200 mM and pH 8.5 of borate buffer conditions were critical. High-speed separation for the neutral monosaccharides (50 s) and for amino monosaccharides (70 s) was attained at a 400 V/cm of electric field condition, showing all peak resolutions were greater than 0.9% and RSD of mobility were less than 1.9%. The detection limits of 0.86 microM for Glc and <1 microM for all other monosaccharides were enhanced with the addition of 0.5% w/v methylcellulose to the buffer. These attainments are fully compatible with conventional CE. The analysis of the subtle differences in the conformational stability and the value of the hydroxyl residue of the borate complex allowed the development of an efficient prospective tool for attaining high-resolution separation of monosaccharide mixtures having complicated and analogous conformations.