Separation of isomaltose from high sugar concentrated enzyme reaction mixture by dealuminated β-zeolite

Study of zeolite clinoptilolite d-glucose adsorption properties in vitro and in vivo

Beneficial effects of a natural zeolite clinoptilolite in vivo on mammals, including humans, have been empirically observed and documented in literature. The positive biological activities have been associated to its detoxifying and antioxidative properties, and its immunostimulative and adsorption properties. Herein, we present the in vitro and in vivo study of clinoptilolite zeolite materials adsorption properties for d-glucose. In particular, we present data on the interaction of d-glucose on the tested zeolites' surface obtained by scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS) and quantification by ultra high-performance liquid chromatography (UHPLC). We also present results on the reduction of blood glucose levels in mice pre-treated with clinoptilolite in vivo upon feeding with d-glucose. In vivo results were in line with the in vitro adsorption and/or interaction properties of tested zeolite materials for d-glucose and were quantified by UHPLC as well (11.34% for TMAZ; 10.82% for PMA and 8.76% for PMAO2). In vivo experiments in mice showed that PMA zeolite reduces blood glucose levels upon 15 min for 13% (at p < 0.05) up to 19.11% upon 120 min (without statistical significance) in clinoptilolite pre-treated mice fed by addition of d-glucose. Due to lack of explicit mechanistic knowledge on zeolite clinoptilolite interactions or adsorption with sugars in vitro and in vivo, presented study provides novel insights into these aspects for researchers in the field. The presented data merit further investigations as the material clearly shows a potential in management of hyperglycemia, such as for example in obese people, people with diabetes and people with metabolic syndrome where it could help regulate blood glucose levels.

Gluco-oligosaccharides as potential prebiotics: Synthesis, purification, structural characterization, and evaluation of prebiotic effect

Prebiotics have long been used to modulate the gut microbiota and improve host health. Most established prebiotics are nondigestible carbohydrates, especially short-chain oligosaccharides. Recently, gluco-oligosaccharides (GlcOS) with 2-10 glucose residues and one or more O-glycosidic linkage(s) have been found to exert prebiotic potentials (not fully established prebiotics) because of their selective fermentation by beneficial gut bacteria. However, the prebiotic effects (non-digestibility, selective fermentability, and potential health effects) of GlcOS are highly variable due to their complex structure originating from different synthesis processes. The relationship between GlcOS structure and their potential prebiotic effects has not been fully understood. To date, a comprehensive summary of the knowledge of GlcOS is still missing. Therefore, this review provides an overview of GlcOS as potential prebiotics, covering their synthesis, purification, structural characterization, and prebiotic effect evaluation. First, GlcOS with different structures are introduced. Then, the enzymatic and chemical processes for GlcOS synthesis are critically reviewed, including reaction mechanisms, substrates, catalysts, the structures of resultant GlcOS, and the synthetic performance (yield and selectivity). Industrial separation techniques for GlcOS purification and structural characterization methods are discussed in detail. Finally, in vitro and in vivo studies to evaluate the non-digestibility, selective fermentability, and associated health effects of different GlcOS are extensively reviewed with a special focus on the GlcOS structure-function relationship.

Structure, function and enzymatic synthesis of glucosaccharides assembled mainly by α1 → 6 linkages - A review

A variety of glucosaccharides composed of glucosyl residues can be classified into α- and β-type and have wide application in food and medicine areas. Among these glucosaccharides, β-type, such as cellulose and α-type, such as starch and starch derivatives, both contain 1 → 4 linkages and are well studied. Notably, in past decades also α1 → 6 glucosaccharides obtained increasing attention for unique physiochemical and biological properties. Especially in recent years, α1 → 6 glucosaccharides of different molecular weight distribution have been created and proved to be functional. However, compared to β- type and α1 → 4 glucosaccharides, only few articles provide a systematic overview of α1 → 6 glucosaccharides. This motivated, the present first comprehensive review on structure, function and synthesis of these α1 → 6 glucosaccharides, aiming both at improving understanding of traditional α1 → 6 glucosaccharides, such as isomaltose, isomaltooligosaccharides and dextrans, and to draw the attention to newly explored α1 → 6 glucosaccharides and their derivatives, such as cycloisomaltooligosaccharides, isomaltomegalosaccharides, and isomalto/malto-polysaccharides.

Vapor- and Liquid-Phase Adsorption of Alcohol and Water in Silicalite-1 Synthesized in Fluoride Media

In this work, batch-adsorption experiments and molecular simulations are employed to probe the adsorption of binary mixtures containing ethanol or a linear alkane-1,n-diol solvated in water or ethanol onto silicate-1. Since the batch-adsorption experiments require an additional relationship to determine the amount of solute (and solvent adsorbed, as only the bulk liquid reservoir can be probed directly, molecular simulations are used to provide a relationship between solute and solvent adsorption for input to the experimental bulk measurements. The combination of bulk experimental measurements and simulated solute-solvent relationship yields solvent and solute loadings that are self-consistent with simulation alone, and allow for an assessment of the various assumptions made in literature. At low solution concentrations, the solute loading calculated is independent of the assumption made. At high concentrations, a negligent choice of assumption can lead to systematic overestimation or underestimation of calculated solute loading.

Continuous enzymatic production and adsorption of laminaribiose in packed bed reactors

Bienzymatic production of laminaribiose from sucrose and glucose was combined with adsorption on zeolite BEA to introduce a first capture and purification step. Downstream processing including washing and desorption steps was characterized and optimized on a milliliter scale in batch mode. Results were then transferred to a packed bed system for enzymatic production and adsorption where the influence of adsorbent particle diameter on purity and productivity was evaluated. Finally, a continuous enzymatic production of laminaribiose was conducted over 10 days. The subsequent downstream processing of the loaded zeolites led to purities of over 0.5 g_{Laminaribiose} g_sugar ^-1 in the desorbate with a total productivity of 5.6 mg_{Laminaribiose} L_{enzyme bed} ^-1 h^-1 without the use of recycles.

A Review of Biorefinery Separations for Bioproduct Production via Thermocatalytic Processing

With technological advancement of thermocatalytic processes for valorizing renewable biomass carbon, development of effective separation technologies for selective recovery of bioproducts from complex reaction media and their purification becomes essential. The high thermal sensitivity of biomass intermediates and their low volatility and high reactivity, along with the use of dilute solutions, make the bioproducts separations energy intensive and expensive. Novel separation techniques, including solvent extraction in biphasic systems and reactive adsorption using zeolite and carbon sorbents, membranes, and chromatography, have been developed. In parallel with experimental efforts, multiscale simulations have been reported for predicting solvent selection and adsorption separation. We discuss various separations that are potentially valuable to future biorefineries and the factors controlling separation performance. Particular emphasis is given to current gaps and opportunities for future development.

Expanding the elution by characteristic point method to columns with a finite number of theoretical plates

The elution by characteristic point (ECP) method provides a rapid approach to determine whole isotherm data with small material usage. It is especially desired wherever the adsorbent or the adsorbate is expensive, toxic or only available in small amounts. However, the ECP method is limited to adsorbents that are well optimized for chromatographic use and therefore provide a high number of theoretical plates when packed into columns (2000 or more for Langmuir type isotherms are suggested). Here we present a novel approach that uses a new profile correction to apply the ECP method to poorly optimized adsorbents with less than 200 theoretical plates. Non-ideality effects are determined using a dead volume marker injection and the resulting marker profile is used to compensate the named effects considering their dependency from the actual concentration instead of assuming rectangular profiles. Experimental and literature data are used to compare the new ECP approach with batch method results.

Extending synthetic routes for oligosaccharides by enzyme, substrate and reaction engineering

The integration of all relevant tools for bioreaction engineering has been a recent challenge. This approach should notably favor the production of oligo- and polysaccharides, which is highly complex due to the requirements of regio- and stereoselectivity. Oligosaccharides (OS) and polysaccharides (PS) have found many interests in the fields of food, pharmaceuticals, and cosmetics due to different specific properties. Food, sweeteners, and food ingredients represent important sectors where OS are used in major amounts. Increasing attention has been devoted to the sophisticated roles of OS and glycosylated compounds, at cell or membrane surfaces, and their function, e.g., in infection and cancer proliferation. The challenge for synthesis is obvious, and convenient approaches using cheap and readily available substrates and enzymes will be discussed. We report on new routes for the synthesis of oligosaccharides (OS), with emphasis on enzymatic reactions, since they offer unique properties, proceeding highly regio- and stereoselective in water solution, and providing for high yields in general.

Adsorption of the compounds encountered in monosaccharide dehydration in zeolite beta

A comprehensive study of the adsorption of the compounds involved in the reaction of dehydration of fructose to 5-hydroxymethyl furfural (HMF) on the zeolite H-BEA with SiO2/Al2O3 = 18 has been carried out. Furthermore, a method for the estimation of the real adsorption loading from the experimentally measured excess adsorption is developed and applied to calculate the adsorption isotherms both in the case of single-solute and multisolute mixtures. It was found that zeolite H-BEA adsorbs HMF and levulinic acid from water mixtures to greater extent than sugars and formic acid, which prefer to partition in the aqueous phase. HMF and levulinic acid adsorption isotherms could be fitted in a Redlich-Peterson isotherm model, while the adsorption of formic acid is better fitted using the Freundlich model and sugars via the Henry model. Adsorption loadings decreased with increasing temperature (0, 25, and 40 °C), which is characteristic of an exothermic process. From the temperature dependence of the isotherms, the limiting heat of adsorption at zero coverage was determined using van't Hoff equation. Given the importance and the complexity of multicomponent systems, several experiments of adsorption of multisolute solutions have been carried out. In most of the cases, the ideal adsorbed solution theory (IAST) has been proven to satisfactorily predict adsorption from multisolute mixtures using as input the single-solute isotherms.

Will isomalto-oligosaccharides, a well-established functional food in Asia, break through the European and American market? The status of knowledge on these prebiotics

This critical review article presents the current state of knowledge on isomalto-oligosaccharides, some well known functional oligosaccharides in Asia, to evaluate their potential as emergent prebiotics in the American and European functional food market. It includes first a unique inventory of the different families of compounds which have been considered as IMOs and their specific structure. A description has been given of the different production methods including the involved enzymes and their specific activities, the substrates, and the types of IMOs produced. Considering the structural complexity of IMO products, specific characterization methods are described, as well as purification methods which enable the body to get rid of digestible oligosaccharides. Finally, an extensive review of their techno-functional and nutritional properties enables placing IMOs inside the growing prebiotic market. This review is of particular interest considering that IMO commercialization in America and Europe is a topical subject due to the recent submission by Bioneutra Inc. (Canada) of a novel food file to the UK Food Standards Agency, as well as several patents for IMO production.

Sodium, ammonium, calcium, and magnesium forms of zeolite Y for the adsorption of glucose and fructose from aqueous solutions

The kinetics of adsorption by sodium, ammonium, calcium and magnesium forms of zeolite Y from aqueous solutions containing 25% w/v of either one or an equimolar mixture of glucose (G) and fructose (F) have been studied batch-wise at 50 degrees C. The adsorption of aqueous pure G was fast, while that of aqueous pure F depended on the cationic form, approaching that of G on the Mg-Y, and slowing down in the sequence of Mg2+ > NH4+ > Ca2+ > Na+ of the cations. The adsorption behavior from solutions containing both G and F indicated significant hindering effects of F on G on Na-Y. Na-Y and Mg-Y did not exhibit rate-based selectivity, while Ca-Y an NH4-Y adsorbed G faster than F. Addition of CaCl2 to the mixture of Ca-Y and aqueous solution of G and F improved the separation, by hindering the adsorption of F. Addition of NH4Cl to the mixture of the sugar solution and NH4-Y, on the other hand, had a negative effect on the separation. NH4-Y was found to be desorbing about 30% of the adsorbed sugars and this value was found to be around 50% for Ca-Y. Re-adsorption experiments resulted in similar or somewhat higher percentages of amounts adsorbed compared to adsorption on fresh samples. Both NH4-Y and Ca-Y were found to be re-adsorbing around 50% of the sugars they adsorbed on fresh samples.