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BACKGROUND: Acidic hydrolysis of a birch (Betula pendula) xylan produced by a novel semi‐industrial‐scale aqueous‐based and highly sustainable method was studied in a batch reactor. Five commercial acidic heterogeneous catalysts were screened and significant differences in their performance were observed. Dowex 50WX2‐100 was selected for further studies and the influence of the reaction parameters, including stirring speed, pH (0.5–1.5), temperature (115–145 °C) and catalyst particle size (50–400 mesh) were studied. The goal was to maximize xylose yield by balancing between the kinetics of hydrolysis and the undesired degradation of monosaccharides. RESULTS: The results show that the maximum achieved yield of xylose was 76%, but higher yields were hindered by the consecutive dehydration of sugars. It was also observed that the hydrolysis and dehydration reactions do not follow the same dependence on the experimental parameters, which leaves room for optimization of the yield. A kinetic model was developed based on the data, which takes into account the consecutive reaction pathway and the influence of the experimental conditions, and a very good fit of the model to the experimental data was achieved. An activation energy of 119 and 88 kJ mol–1 was obtained for the hydrolysis and dehydration steps, respectively. CONCLUSION: Hydrolysis results of this novel, well‐characterized hemicellulose extract have not been published previously, and they contribute significantly to the understanding of the hydrolysis and dehydration of real feedstock, instead of highly purified and typically very deacetylated model compounds with different characteristics and behaviour in hydrolysis. © 2021 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Basing on the simplest hydrothermal system containing deionized water, hexa-ammonium molybdate, and thiourea, hydrothermal mechanism on preparation of MoS2 was studied by DFT calculation. Hydrothermal process was divided into four steps which covered ionization equilibrium, the hydrolysis of CS(NH2)2, the formation of intermediates, and the formation of MoS2. Ionization equilibrium occurs at normal condition and determines the existence of Mo in the form of molybdic acid. Thiourea hydrolysis is rate-determining step in the process of hydrothermal which contains 10 elementary reactions. The formation of intermediates includes hydrogen transfer, dehydration, and vulcanization three steps which contain 18 elementary reactions, and the energy barrier of vulcanization is the highest. The formation of MoS2 is divided into two steps, the first step is that MoO(OH)(SH)3.H2O reacts with MoO (SH)4.H2O to form layer MoS2, and the second step is a very fast process that can affect the morphology of the products. [ABSTRACT FROM AUTHOR]

Magnesium chloride hydrates are characterized as promising energy storage materials in the built-environment. During the dehydration of these materials, there are chances for the release of harmful HCl gas, which can potentially damage the material as well as the equipment. Hydrolysis reactions in magnesium chloride hydrates are subject of study for industrial applications. However, the information about the possibility of hydrolysis reaction, and its preference over dehydration in energy storage systems is still ambiguous at the operating conditions in a seasonal heat storage system. A density functional theory level study is performed to determine molecular structures, charges, and harmonic frequencies in order to identify the formation of HCl at the operating temperatures in an energy storage system. The preference of hydrolysis over dehydration is quantified by applying thermodynamic equilibrium principles by calculating Gibbs free energies of the hydrated magnesium chloride molecules. The molecular structures of the hydrates (n = 0, 1, 2, 4, and 6) of MgCl2 are investigated to understand the stability and symmetry of these molecules. The structures are found to be noncomplex with almost no meta-stable isomers, which may be related to the faster kinetics observed in the hydration of chlorides compared to sulfates. Also, the frequency spectra of these molecules are calculated, which in turn are used to calculate the changes in Gibbs free energy of dehydration and hydrolysis reactions. From these calculations, it is found that the probability for hydrolysis to occur is larger for lower hydrates. Hydrolysis occurring from the hexa-, tetra-, and di-hydrate is only possible when the temperature is increased too fast to a very high value. In the case of the mono-hydrate, hydrolysis may become favorable at high water vapor pressure and at low HCl pressure. [ABSTRACT FROM AUTHOR]

Sodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage. [ABSTRACT FROM AUTHOR]

High-purity anhydrous MgCl2-containing molten salt was directly synthesized from MgCl2 · 6H2O via complex salts dehydration and protection. After that, Mg-Al and Mg-Zn alloys were prepared by electrochemical codeposition. The hydrolysis processes of magnesium chloride hexahydrate in various chloride mixtures were studied. Then, the preparation process was studied and the dehydration mechanism was put forward. NH4Cl·MgCl2·nH2O formed under 300°C inhibits the formation of hydrolysate during the dehydration process. KMgCl3 and K3NaMgCl6 formed above 400°C can further protect the unstable anhydrous MgCl2. Therefore, high-purity anhydrous MgCl2-containing molten salt with w(MgO)/w(MgCl2) being 0.016 wt.% was obtained. The current efficiency was above 81% and 97%, respectively, when preparing Mg-Al alloys and Mg-Zn alloys, and the alloying elements were distributed homogeneously in the alloy matrix. [ABSTRACT FROM AUTHOR]

Abstract The goal of this study was to investigate changes in nutritional quality of fish silage during refractance window (RW) drying. Furthermore, the effect of protein hydrolysis-degree of fish silage on production efficiency (%-moisture evaporated and production rate) was determined. To acquire a dried product, fish silage was conveyed (30 cm/min) on a polyester film over a water bath of 55 °C. Moisture content decreased from 747 ± 24 g/kg to 101 ± 33 g/kg, with only a slight increase in TBARS, from 3.7 ± 1.0 mg/kg to 6.3 ± 0.8 mg/kg. End-product consistency seemed to be affected by application thickness, ambient conditions and protein hydrolysis-degree. Additionally, a higher protein hydrolysis-degree increased evaporation efficiency, resulting in moisture contents of 135 ± 10 g/kg, 101 ± 12 g/kg, and 67 ± 24 g/kg, for low-DH, medium-DH, and high-DH, respectively; though production rate decreased, producing dry matter outputs of 1.60 ± 0.06 kg/h, 1.21 ± 0.03 kg/h, and 1.05 ± 0.06 kg/h, respectively, possibly caused by an increased availability of free water and a reduced application thickness. RW-drying seems to be an effective way of rapidly drying fish silage under gentle conditions. Highlights • TBARS in fish silage slightly increased during RW-drying. • Total volatile nitrogen and trimethylamine remained stable during RW-drying. • Application thickness and degree of protein-hydrolysis affected product consistency. • Higher protein-hydrolysis degree in fish silage increases evaporation efficiency. • Higher protein-hydrolysis degree in fish silage reduces production rate. [ABSTRACT FROM AUTHOR]

Highlights • A. niger CECT 2700 produced an enzymatic cocktail by SSF of lignocellulosic wastes. • Cocktail contains xylanases, celluloses, cellobiases and feruloyl esterases. • Hydrolysis of raw BSG with enzymatic cocktail produced high sugar-containing media. • Pretreatment of BSG improve the xylose release during the enzymatic hydrolysis. • Enzymatic cocktails could be used for biorefinery and biocatalysis processes. Abstract Lignocellulosic biomass is a feedstock with the potential to be converted into value-added bioproducts. The use of enzymatic hydrolysis allows the cleavage of lignocellulose into their monomeric units, but there are some drawbacks that make its use in industrial biocatalysis unfeasible. In the present study, we describe the hydrolysis of brewer's spent grain (BSG) with an enzymatic cocktail produced by Aspergillus niger CECT 2700 and its comparison with commercial enzymes. In addition, it was determined whether pretreating the BSG (non-pressurized alkaline hydrolysis or treatment with cholinium glycinate ionic liquid) is necessary. Results show that both pretreatments enhanced xylose release (10.55 ± 0.07 g/L and 8.14 ± 0.13 g/L respectively), meanwhile the hydrolysis of raw BSG with the enzymatic cocktail produced solutions containing high levels of glucose (18.45 ± 1.66 g/L) and xylose (6.38 ± 0.26 g/L). [ABSTRACT FROM AUTHOR]

Abstract The possible hydrolysis of various Novichok agents and products of their degradation by organophosphorus hydrolase (OPH) and its genetically His 6 -modified form was investigated by computer modeling via docking of substrate to enzyme active center. Magnitude of potential values of catalytic characteristics of enzyme(s) with such substrates was estimated. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Catalytic conversion (hydrolysis) of carbohydrate polymers present in the lignocellulosic biomass into fermentable sugars is a key step in the production of bioethanol. Although, acid and enzymatic catalysts are conventionally used for the catalysis of various lignocellulosic biomass, recently application of immobilized enzymes (biocatalysts) have been considered as the most promising approach. Immobilization of different biocatalysts such as cellulase, β-glucosidase, cellobiose, xylanase, laccase, etc. on support materials including nanomaterials to form nanobiocatalyst increases catalytic efficacy and stability of enzymes. Moreover, immobilization of biocatalysts on magnetic nanoparticles (magnetic nanobiocatalysts) facilitates easy recovery and reuse of biocatalysts. Therefore, utilization of nanobiocatalysts for catalysis of lignocellulosic biomass is helpful for the development of cost-effective and ecofriendly approach. In this review, we have discussed various conventional methods of hydrolysis and their limitations. Special emphasis has been made on nanobiocatalysts used for hydrolysis of lignocellulosic biomass. Moreover, the other most important aspects, like nanofiltration of biomass, conversion of lignocellulose to nanocellulose, and toxicological issues associated with application of nanomaterials are also discussed. [ABSTRACT FROM AUTHOR]

Life as we know it requires three basic types of polymers: polypeptide, polynucleotide, and polysaccharide. Here we evaluate both universal and idiosyncratic characteristics of these biopolymers. We incorporate this information into a model that explains much about their origins, selection, and early evolution. We observe that all three biopolymer types are pre-organized, conditionally self-complementary, chemically unstable in aqueous media yet persistent because of kinetic trapping, with chiral monomers and directional chains. All three biopolymers are synthesized by dehydration reactions that are catalyzed by molecular motors driven by hydrolysis of phosphorylated nucleosides. All three biopolymers can access specific states that protect against hydrolysis. These protected states are folded, using self-complementary interactions among recurrent folding elements within a given biopolymer, or assembled, in associations between the same or different biopolymer types. Self-association in a hydrolytic environment achieves self-preservation. Heterogeneous association achieves partner-preservation. These universal properties support a model in which life's polymers emerged simultaneously and co-evolved in a common hydrolytic milieu where molecular persistence depended on folding and assembly. We believe that an understanding of the structure, function, and origins of any given type of biopolymer requires the context of other biopolymers. [ABSTRACT FROM AUTHOR]

Cycles of biologically relevant reactions are an alternative to an origin of life emerging from a steady state away from equilibrium. The cycles involve a rate at which polymers are synthesized and accumulate in microscopic compartments called protocells, and two rates in which monomers and polymers are chemically degraded by hydrolytic reactions. Recent experiments have demonstrated that polymers are synthesized from mononucleotides and accumulate during cycles of hydration and dehydration, which means that the rate of polymer synthesis during the dehydrated phase of the cycle is balanced (but not dominated) by the rate of polymer hydrolysis during the hydrated phase of the cycle. Furthermore, depurination must be balanced by the reverse process of repurination. Here we describe a computational model that was inspired by experimental results, can be generalized to accommodate other reaction parameters, and has qualitative predictive power. [ABSTRACT FROM AUTHOR]

This study investigated the use of 30 w/v% H 2 SO 4 sulfonated wood waste-derived biochar as catalysts for production of value-added chemicals from carbohydrates in water as an environmentally benign solvent. Physicochemical characteristics of the sulfonated biochar were revealed by Fourier transform infrared spectroscopy (FTIR), acid-base neutralization titration, gas adsorption analysis, thermogravimetric analysis (TGA), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Using the sulfonated biochar as catalysts, hydrolysis of maltose at 140–160 °C resulted in the maximum glucose yield of 85.4% and selectivity of 88.2%, whereas dehydration of fructose at 160–180 °C produced the maximum HMF yield of 42.3% and selectivity of 60.4%. A higher range of reaction temperature was required for fructose dehydration due to the higher energy barrier compared to maltose hydrolysis. While increasing the temperature accelerated the catalytic reactions, the maximum product selectivity remained unchanged in the sulfonated biochar-catalyzed systems. The products were stable despite the increase in reaction time, because rehydration and adsorption of products was found to be minor although polymerization of intermediates led to unavoidable carbon loss. This study highlights the efficacy of engineered biochars in biorefinery as an emerging application. [ABSTRACT FROM AUTHOR]

To develop resistant starch (RS) nanoparticles, waxy rice starch was hydrolyzed with acid for 10 days, and acid-hydrolyzed waxy rice starch (AHW) was cross-linked with sodium trimetaphosphate. The RS nanoparticles were collected by freeze-drying (FD), freeze-drying after sonication (SFD), and ethanol dehydration after sonication (SE). The particle size distribution, RS level by modified AOAC, zeta potential, and stability of dispersion were assessed. The hydrolysis rate ranged from 44.62% to 49.43%, and AHW particle size decreased as hydrolysis time increased. All AHW and RS nanoparticles showed A type crystallinity. The particle size and zeta potential of the nanoparticles dried by FD, SFD, and SE were 300.0, 211.9, and 459.7 nm and −37.1, −43.0, and −35.4 mV, respectively. The RS levels were increased by cross-linking. The SFD dispersion was the most stable. The results indicate that the RS4 nanoparticles, for applying to liquid foods, can be prepared by acid hydrolysis, cross-linking, and SFD. [ABSTRACT FROM AUTHOR]

Acidic hydrolysis is commonly used as a first step to break down oligo- and polysaccharides into monosaccharide units for structural analysis. While easy to set up and amenable to mass spectrometry detection, acid hydrolysis is not without its drawbacks. For example, ring-destruction side reactions and degradation products, along with difficulties in optimizing conditions from analyte to analyte, greatly limits its broad utility. Herein we report studies on a hydrogen peroxide/CuGGH metallopeptide-based glycosidase mimetic design for a more efficient and controllable carbohydrate hydrolysis. A library of methyl glycosides consisting of ten common monosaccharide substrates, along with oligosaccharide substrates, was screened with the artificial glycosidase for hydrolytic activity in a high-throughput format with a robotic liquid handling system. The artificial glycosidase was found to be active towards most screened linkages, including alpha- and beta-anomers, thus serving as a potential alternative method for traditional acidic hydrolysis approaches of oligosaccharides. [ABSTRACT FROM AUTHOR]

The functional and in vitro antioxidant properties of common kilka fish protein hydrolysates with different degree of hydrolysis (DH) obtained by kiwifruit protease (KP) and ginger protease (GP) were evaluated. The electrophoretic patterns of hydrolysates showed the presence of one major band in different DHs with a molecular weight of less than 25 kDa. Protein solubility was positively correlated with DH, and the solubility of KP and GP hydrolysates (HKP and HGP, respectively) at 15% DH was higher than other DHs (p ≤ 0.05). Higher emulsifying and foaming properties were observed in HKP over a pH range of 2-10 (p ≤ 0.05), and in vitro antioxidant activity was higher in HKP at 15% DH as seen from 2,2-diphenyl-1-picrylhydrazyl radical scavenging and ferric-reducing power. Thus, the results reveal that DH and enzyme type affects functional properties and antioxidant activity of the hydrolysates. [ABSTRACT FROM AUTHOR]

Synthesis of new furoxan-based compounds has been a hot research topic in order to explore the energetic materials with good application prospect. 3-amino-4-nitro-furoxan is a precursor for synthesis of furoxan derivatives because that the amino groups are prone to be substituted by nucleophiles. A theoretical research is conducted for the formation reaction of 3-amino-4-nitro-furoxan by 3-amide-4-nitro-furoxan and sodium hypochlorite in water and benzene solvents using the density functional theory (DFT) and CCSD coupled cluster method to reveal the formation mechanism and explore new synthesis routes. The structures and energies of intermediates and transition states in the possible reaction pathways are given, and the potential energy surfaces of the every reaction channels are mapped. The results indicate that the formation mechanism is mainly through two stages: generation and hydrolysis of isocyanate. Hydrogen bond plays an important role for the hydrolysis process. The formation mechanism is shown to be dependent on the polarity of solvent. The hydroxyl ion (OH − ) , originated from the basic properties of sodium hypochlorite solution, is shown to be more likely first attacker than the hypochlorite ion (OCl − ) for the reactant 3-amide-4-nitro-furoxan due to the low active barrier in the polar water solvent. But the OCl − dominates the reaction in benzene solvent where the isocyanate is formed via the dehydration chlorination by OCl − and Hofmann rearrangement with the elimination of chloride ion. The isocyanate is then hydrolyzed through addition of a H 2 O molecule to the N C double bonds, rotation of the hydroxyl hydrogen, transfer of hydrogen to the N atom in the amide group and the removal of a CO 2 molecule to form the final product. The benzene solvent is more suitable than water solvent for the formation reaction due to the lower active barrier of 46.4 kcal/mol. The reaction is not feasible at room temperature and raising properly temperature of system would be requisite to realize the synthesis reaction. [ABSTRACT FROM AUTHOR]

Relationship between concentration of sulfuric acid (C) and temperature (T) required for the cellulose hydrolysis to prepare nanocrystalline particles (NCP has been studied in this paper. The experiments showed that there is a linear C and T superposition exists, namely: C= Co - n T. The higher the acid concentration, the lower the hydrolysis temperature should be used, and vice versa. If temperature or acid concentration is lower, there is a tendency to form of microparticles. On the other hand, at higher hydrolysis temperatures, carbonized CNP with decreased yield are obtained. The maximum level of acid concentration that can be used for production of CNP is 60 % at optimal temperature of 45°C. The rod-like crystalline nanoparticles of cellulose produced at these hydrolysis conditions have average sizes of 160 x 14 nm, degree of crystallinity of 75-77% and degree of polymerization of 120-140. The nanoparticles form stable colloidal dispersions in water due to effect of Brownian motion and negative Zeta potential. The economical calculations of production of two cellulose nanoproducts, paste and beads of CNP, showed that the production of paste is much cheaper. The proposed technology provides the complete utilization of acidic wastewater and their use for the production of valuable by-product such as superphosphate fertilizer, the selling of which covers part of the production cost of NCP. The cheap cellulose nano-product, paste of NCP, was obtained without discharge of production waste into the environment. Furthermore, all washing water is returned in the production line. To reduce the production expenses it is most advantageous to use 60% concentration of SA and relative low hydrolysis temperature, 45°C. [ABSTRACT FROM AUTHOR]

A principal challenge in using biomass as a replacement for petroleum has been to develop cost-competitive and sustainable processing technology. Cellulose in biomass can be converted into levulinic and formic acids through acid-catalyzed hydrolysis and dehydration, conventionally done using sulfuric acid. These products can be used as chemical feedstocks or converted to advanced biofuels. Product separation and sulfuric acid recovery are significant hurdles hindering the commercialization of the acid-catalyzed process. Hydrolysis of cellulose using α-hydroxysulfonic acids (αHSAs) presents a novel approach to simplifying acid recovery from biomass hydrolysates. We present the results of comparing six different αHSAs, including two derived from molecules produced by the hydrolysis itself, for conversion of glucose or cellulose to levulinic acid. After evaluating the six compounds for qualities of catalytic activity, thermal stability, and recyclability, we found that acetone-derived αHSA compares favorably in terms of these metrics. Highest yields of levulinic acid derived from cellulose were 40% of theoretical, achieved at conditions of 150 °C, 24 h reaction time, 3% cellulose feed, and 1.875 M acetone-derived αHSA. [ABSTRACT FROM AUTHOR]

Given the strong demands for high purity vanadium products dedicated for all-vanadium redox flow battery (VRFB), numerous preparation technologies have been developed. One of them, the chloride process that using vanadium oxytrichloride (VOCl 3 ) as purification intermediate presents distinct technical advantages. The intermediate is readily purified via distillation process to remove most of the impurities. However, the trace titanium tetrachloride (TiCl 4 ) is difficult to be removed, due to close saturated vapor pressures. In present work, based on thermodynamic calculation and analyses, we found that TiCl 4 reacts with water significant preferentially to form the corresponding oxide, compared with VOCl 3 . Then we proposed a novel method to remove trace TiCl 4 from VOCl 3 by selective hydrolysis – distillation. The related experiments were conducted and validated the feasibility of the innovative process. Vanadium pentoxide (V 2 O 5 ) with purity higher than 99.99 wt% (4N) was further prepared from the purified VOCl 3 by precipitation – calcination. [ABSTRACT FROM AUTHOR]

Magnesium-silica-hydrates (M-S-H) is a promising binder for magnesia castables due to its bonding strength and progressive dehydration behavior over a wide temperature range during the heating-up stage. Sodium metasilicate and caustic magnesia were used to form M-S-H in magnesia castables. The results showed that M-S-H was remarkably produced in the caustic magnesia-microsilica slurries containing sodium metasilicate with increasing pH value, which activated the hydrolysis of microsilica into silicic ions and enhanced the M-S-H formation. When 0.3 wt% caustic magnesia and 0.05 wt% sodium metasilicate as additives were incorporated into magnesia castables, the cold crushing strength and cold modulus of rupture of castables after drying at 110 °C reached the maximum value of 68.3 MPa, which corresponded to ~ 40% improvement in comparison with those of caustic magnesia and sodium metasilicate-free magnesia castables. Besides, the enhanced formation of M-S-H bonding system contributed to a better explosion resistance of magnesia castables. [ABSTRACT FROM AUTHOR]

Hydrolysis of an open-cage C60 derivative in a mixture of HCl/AcOH/H2O resulted in removal of two hydroxyl groups, one carbonyl group and one aniline group in one step. A domino mechanism is proposed for the process. The newly formed open-cage C60 derivative has three carbonyl groups on the rim of the orifice, one of which could be converted into an oxime group by treatment with hydroxylamine. [ABSTRACT FROM AUTHOR]

The consumption of fossil fuels in excess leads to chronic effect of greenhouse gas (GHG) emissions on the environment. These adverse environmental impacts of GHG have invoked reasonable awareness on renewable energy resources. Bioethanol from lignocellulosic agricultural residue (profusely available renewable raw materials in the tropical areas) exhibits promising alternative to the petroleum based fossil fuel which reduces the net emission of GHGs. But due to certain technological barriers the large scale production of lignocellulosic bioethanol has not been successfully commercialized. To achieve the goal, economically viable bioethanol production technology, which includes pretreatment, enzymatic hydrolysis, fermentation, and dehydration, needs to be developed. Ionic liquid aided pretreatment can recover more than 80% cellulose and 42% lignin from lignocelluloses, which generally contains 30–46% cellulose and 18–25% lignin. Processing of the recovered cellulose towards bioethanol production requires enzymatic hydrolysis, which gives almost 76% reducing sugar yield. Use of ultrafiltration and nanofiltration in hydrolysis concentrates 27% reducing sugar as well as recovers more than 73% enzyme with 50% catalytic activity. Ultrafiltration rejects 100% yeast as well as reveals 15 g/l/h ethanol productivity, which can be subjected to membrane based dehydration by way of pervaporation to produce 99.8 wt% ethanol. The scope of this review focuses on eco-friendly and sustainable method for bioethanol production. A holistic and dedicated approach of this review helps to solve the various technological concerns and realize large scale commercialization of lignocellulosic ethanol. [ABSTRACT FROM AUTHOR]

The controllable photocatalytic hydrolysis of alkali-metal borohydrides is studied for hydrogen generation in this work. The results indicate that the photocatalysis of P25 TiO2 controllably promotes the hydrogen generation rates from alkali-metal borohydride hydrolysis. Its apparent activation energy is calculated to be reduced from 57.20 to 53.86 kJ mol−1. This is due to the mechanism of photocatalytic hydrolysis: holes (h+) react with BH4- and OH− to form H2 and B(OH)4-, meanwhile electrons (e−) react with H+ to from H2. In addition, Ti3+-doped TiO2 with a crystalline-disordered core-shell structure can be generated during the photocatalytic hydrolysis process. The consumption of e− is identified as the rate-limiting step in photocatalytic hydrolysis process. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT We have demonstrated a hydrolysis reaction of polyurethane (PU) under high pressure of carbon dioxide (CO2) in water. We employed the PU sample, poly(methylene bis-(1,4-phenylene)hexamethylene dicarbamate), denoted as M-PU, which was synthesized from 4,4′-diphenyl methane diisocyanate and 1,4-butane diol (BD). The optimum hydrolysis reaction condition was 190 °C under CO2 pressures over 4.1 MPa in water medium, and 93% hydrolysis of M-PU was achieved. After the reaction, the water-soluble parts were obtained, and isolated by column chromatography. The isolated products were 4,4′-methylenedianiline (MDA) and 1,4-butane diol (BD), which were components of repeating unit of M-PU. In addition, the hydrolysis reaction gave no byproduct. This hydrolysis under high pressure of CO2 with water is a reaction by which M-PU is selectively hydrolyzed into MDA and BD by cleaving urethane linkage. Moreover, the resulting hydrolyzed products were easily obtained by evaporation of aqueous layer after the reaction, indicating an efficient chemical recycling of PU was achieved. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2004-2010 [ABSTRACT FROM AUTHOR]

ABSTRACT We have demonstrated a hydrolysis reaction of polyurethane (PU) under high pressure of carbon dioxide (CO2) in water. We employed the PU sample, poly(methylene bis-(1,4-phenylene)hexamethylene dicarbamate), denoted as M-PU, which was synthesized from 4,4′-diphenyl methane diisocyanate and 1,4-butane diol (BD). The optimum hydrolysis reaction condition was 190 °C under CO2 pressures over 4.1 MPa in water medium, and 93% hydrolysis of M-PU was achieved. After the reaction, the water-soluble parts were obtained, and isolated by column chromatography. The isolated products were 4,4′-methylenedianiline (MDA) and 1,4-butane diol (BD), which were components of repeating unit of M-PU. In addition, the hydrolysis reaction gave no byproduct. This hydrolysis under high pressure of CO2 with water is a reaction by which M-PU is selectively hydrolyzed into MDA and BD by cleaving urethane linkage. Moreover, the resulting hydrolyzed products were easily obtained by evaporation of aqueous layer after the reaction, indicating an efficient chemical recycling of PU was achieved. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2004-2010 [ABSTRACT FROM AUTHOR]

The study examined catalytic conversion of diethyl ether in a gas phase in the static system on the synthetic mordenite (NaM) and the mordenite which the bivalent cobalt cation was introduced into (CoM). The reaction was observed in the temperature range from 424 K to 653 K, and the reaction products on both catalysts were ethene and water, and on NaM a small quantity of butene. The reaction of diethyl ether dehydration in the observed temperature interval is accelerate in time. The initial reaction is registered at the very beginning of the reaction followed by the water occurrence. The water originating from the reaction is generated on the surface of the zeolite catalyst the active centers that is favorable for the dehydration reaction. With the temperature growth the initial period on NaM catalyst gradually disappears and the reaction becomes the first order reaction (temperature is 653 K), while on CoM catalyst the initial period is registered at all observed temperatures. The explanation of the role of water in the occurrence of active centers needed for diethyl ether hydrolysis was obtained by experiments in which water was also added to the reaction mixture of diethyl ether - catalyst. [ABSTRACT FROM AUTHOR]

Solid acid NbO/ZrO catalysts containing 0, 0.5, 1.1 and 2.8 wt.% of Nb were prepared for one-pot hydrolysis-dehydration of mechanically activated cellulose in pure hot water to produce glucose and 5-hydroxymethylfurfural. The catalysts were characterized (XRD, N adsorption, ICP-OES, UV-Vis DRS) and tested in cellulose processing at 453 K. The catalytic activity increased as follows: 0.5%Nb/ZrO < ZrO < < 1.1%Nb/ZrO ~ 2.8%Nb/ZrO. This series was accounted for by the acid-basic properties of ZrO, by the inhibition of its active sites by monomer niobium species and by the appearance of Brønsted acidity upon the formation of NbO-containing polymer structures. The highest glucose and 5-HMF yields (22 and 16 mol%, respectively) were achieved over 2.8%Nb/ZrO. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Conventional production of cellulose nanocrystals (CNC) normally encounters several problems including high energy consumption, toxicity and corrosion risk. Implementation of green solvent ionic liquid (IL) is an alternative to this conventional method. Production of CNC is known to be influenced by several factors such as reaction time and temperature. However, limited studies on the regeneration yield and other properties of CNC produced at both variables can be found. In this paper, CNC with desirable yield, crystallinity and particle size has been produced under catalytic hydrolysis process of IL. Two different parameters have been studied which are reaction temperature and time. It was found that, CNC with particle size of 9 nm and 73% crystallinity index has been produced at 30 min reaction time. Meanwhile, 100 °C reaction temperature manages to produce CNC with 90% yield and 76% crystallinity. In conclusion, reaction temperature and time affect the yield and thermal properties of hydrolysis process. [ABSTRACT FROM AUTHOR]

Rice straw is a renewable, cheap, and abundant resource in agriculture. Due to its controllable and recoverable properties, H 2 O-SO 2 system was studied as a reaction medium to hydrolyze rice straw to produce chemicals by a two-step treatment. The first-step treatment converted hemicellulose to xylose (17.1%), glucose (3.1%) and arabinose (3.5%) at 140 °C. The second-step treatment converted cellulose to glucose (10.9%) at 190 °C. The total yield of products by the two-step treatment of rice straw was 41.1%, which is more than that in the one-step treatment (21.0% at 190 °C). The apparent activation energies for hemicellulose conversion and xylose dehydration were 76.7 and 66.9 kJ/mol, respectively. The degradation products obtained from the two-step treatment are less than that from the one-step treatment. [ABSTRACT FROM AUTHOR]

Chiral spirocarbocyclic skeletons are ubiquitous in natural products. An intramolecular Tsuji-Trost (T-T) α-allylation of simple cyclic ketones is a reasonable approach to construct chiral spriocarbocyclic motifs; however, it has been a challenging approach despite many excellent intermolecular examples. For the first time, this has been achieved by a Ru/H+ combined catalyst that dehydratively cyclizes racemic allylic alcohols comprising a simple ketone via simultaneous activation of the C=O and OH groups. This chiral technology facilitates the construction of various spirocarbocycles containing two contiguous spiro all-carbon quaternary and tertiary stereocenters. Among four possible stereoisomers, one stereoisomer can be selectively produced in high yield, enhancing the feasibility of the T-T strategy, particularly in the synthesis of spirocarbocycles. [ABSTRACT FROM AUTHOR]

Siloxane bonds are usually synthesized by condensation reactions, such as hydrolysis/dehydration and cross-coupling reactions, in which the generation of by-products during bond formation can not be avoided. We have developed a one-pot sequence of iridium-catalyzed silyl ester hydrosilylation and boron-catalyzed rearrangement of the resulting disilyl acetals for the construction of siloxane bonds, in principle without the formation of any by-products. Moreover, the programmed synthesis of tri-, tetra-, and pentasiloxanes was possible in a single flask by combining the above sequence of iridium-catalyzed hydrosilylation and boron-catalyzed rearrangement with a boron-catalyzed cross-coupling reaction. The obtained oligosiloxanes are difficult to synthesize selectively by other known synthetic procedures. [ABSTRACT FROM AUTHOR]

The presence of high concentration antibiotics in wastewater can disturb the stability of biological wastewater treatment systems and promote generation of antibiotic resistance genes (ARGs) during the treatment. To solve this problem, a pilot system consisting of enhanced hydrolysis pretreatment and an up-flow anaerobic sludge bed (UASB) reactor in succession was constructed for treating oxytetracycline production wastewater, and the performance was evaluated in a pharmaceutical factory in comparison with a full-scale anaerobic system operated in parallel. After enhanced hydrolysis under conditions of pH 7 and 85 °C for 6 h, oxytetracycline production wastewater with an influent chemical oxygen demand (COD) of 11,086 ± 602 mg L −1 was directly introduced into the pilot UASB reactor. With the effective removal of oxytetracycline and its antibacterial potency (from 874 mg L −1 to less than 0.61 mg L −1 and from 900 mg L −1 to less than 0.84 mg L −1 , respectively) by the enhanced hydrolysis pretreatment, an average COD removal rate of 83.2%, 78.5% and 68.9% was achieved at an organic loading rate of 3.3, 4.8 and 5.9 kg COD m −3 d −1 , respectively. At the same time, the relative abundances of the total tetracycline ( tet ) genes and a mobile element (Class 1 integron ( intI1 )) in anaerobic sludge on day 96 were one order of magnitude lower than those in inoculated sludge on day 0 (P < 0.01). The reduction of ARGs was further demonstrated by metagenomic sequencing. By comparison, the full-scale anaerobic system treating oxytetracycline production wastewater with an influent COD of 3720 ± 128 mg L −1 after dilution exhibited a COD removal of 51 ± 4% at an organic loading rate (OLR) 1.2 ± 0.2 kg m −3 d −1 , and a total tet gene abundance in sludge was five times higher than the pilot-scale system (P < 0.01). The above result demonstrated that enhanced hydrolysis as a pretreatment method could enable efficient anaerobic treatment of oxytetracycline production wastewater containing high concentrations of oxytetracycline with significantly lower generation of ARGs. [ABSTRACT FROM AUTHOR]

Bio-based phenol formaldehyde (BPF) foams with high phenol substitution ratios (30–50 wt%) were successfully prepared using depolymerized hydrolysis lignin (DHL, M w ≈ 2000 g/mol) obtained via a proprietary low-temperature/low pressure depolymerisation process. FTIR measurements indicated that the foamable BPF resoles and foams had structures very similar to the phenol formaldehyde (PF) resole and foam. The prepared 30% BPF foam had similar apparent density (40 kg/m 3 ), compressive strength (0.152 MPa), elastic modulus (2.16 MPa) and thermal conductivity (0.033 W/m/K) with the PF foam. However, 50% BPF foam showed higher apparent density (108 kg/m 3 ), higher compressive strength (0.405 MPa) and elastic modulus (7.56 MPa) than the PF foam. All BPF foams exhibited satisfactory thermal conductivity (0.033–0.040 W/m/K) and cell structure. TGA analysis demonstrated that the BPF foams had excellent thermal stability at temperatures less than 200 °C. Thus, the BPF foams could be utilized as the insulation and fire resistant materials. [ABSTRACT FROM AUTHOR]

Background: Glycoside hydrolases (GHs) are enzymes that hydrolyze polysaccharides into simple sugars. To better understand the specificity of enzyme hydrolysis within the complex matrix of polysaccharides found in the plant cell wall, we studied the reactions of individual enzymes using glycome profiling, where a comprehensive collection of cell wall glycan-directed monoclonal antibodies are used to detect polysaccharide epitopes remaining in the walls after enzyme treatment and quantitative nanostructure initiator mass spectrometry (oxime-NIMS) to determine soluble sugar products of their reactions. Results: Single, purified enzymes from the GH5_4, GH10, and GH11 families of glycoside hydrolases hydrolyzed hemicelluloses as evidenced by the loss of specific epitopes from the glycome profiles in enzyme-treated plant biomass. The glycome profiling data were further substantiated by oxime-NIMS, which identified hexose products from hydrolysis of cellulose, and pentose-only and mixed hexose-pentose products from the hydrolysis of hemicelluloses. The GH10 enzyme proved to be reactive with the broadest diversity of xylose-backbone polysaccharide epitopes, but was incapable of reacting with glucose-backbone polysaccharides. In contrast, the GH5 and GH11 enzymes studied here showed the ability to react with both glucose- and xylose-backbone polysaccharides. Conclusions: The identification of enzyme specificity for a wide diversity of polysaccharide structures provided by glycome profiling, and the correlated identification of soluble oligosaccharide hydrolysis products provided by oxime- NIMS, offers a unique combination to understand the hydrolytic capabilities and constraints of individual enzymes as they interact with plant biomass. [ABSTRACT FROM AUTHOR]

Wheat straw was pretreated and afterwards enzymatically hydrolyzed using a modified ammonia fiber expansion (AFEX) process under different reaction conditions to produce fermentable sugars. Instead of liquid ammonia, aqueous ammonia (25 % w/ v) was used to test its influence on the sugar concentration and yield of the sugars. It is shown that a protein extraction after the pretreatment can distinctly improve the result obtained for the enzymatic hydrolysis. This modified AFEX process using aqueous ammonia represents a simpler and less expensive variant of the AFEX process usually described in literature. Thus, the described process can be used for the primary refining of lignocellulosic feedstocks in the sense of a roadmap for biorefinery. [ABSTRACT FROM AUTHOR]

This work employs experiments and statistical modelling to characterize three water-regulated regimes (limited/sufficient/inhibited) in two-phase catalytic conversion of lignocelluloses to biofuel precursors. CuCl 2 -catalyzed conversion of two non-edible lignocelluloses (June grass, Sunn hemp) is performed for 24 h using a protic ionic liquid (Triethylammonium hydrogen sulfate) at 110 °C, wherein the temporal dynamics of glucose, 5-Hydroxymethylfurfural (5-HMF), Levulinic acid (LA), and Formic acid (FA) are measured by varying the water-addition. Water, being a substrate in cellulose hydrolysis to glucose (isomerized to fructose), and an inhibitor in fructose dehydration to 5-HMF, regulates product yields through interactions between transport (heat conduction and viscosity) and reaction (non-linear kinetics and activation energy). The yields of glucose and 5-HMF peak at 6 h to 60.2% and 10.2%, respectively, from Sunn hemp, and at 4 h to 62.7% and 12.8%, respectively, from June grass, while those of LA and FA peak at 8 h to 23% and 9.1%, respectively, from Sunn hemp, and at 5 h from 19.3% to 7.7%, respectively, from June grass. The protic ionic liquid is recovered (91.4%) through biphasic separation, glucose is separated (75%) using an anti-solvent, 5-HMF is separated (54%) by liquid-liquid extraction, and LA (58%) and FA (42%) are separated by reactive extraction. The regulatory effects of water on cellulose hydrolysis from Sunn hemp and June grass are quantified (R2 > 0.92) by a linear superposition of two Gaussian distributions representing 'ignited' and 'extinguished' reaction states that delineate the three water-regulated regimes, and allow us to quantify the water-sufficient regime for maximizing product yields. [Display omitted] • Biofuel precursors (glucose, HMF, levulinic and formic acids) from non-edible lignocelluloses (June grass, Sunn hemp). • Temporal dynamics of biofuel precursors from catalytic hydrolysis experiments. • Statistical modelling of regulatory effects of water addition on product yields. • Linear-superposition of two Gaussian distributions (extinguished and ignited states). • Product separation and ionic liquid recycling for cost-effectiveness. [ABSTRACT FROM AUTHOR]

The present work aimed to study the effect of the pretreatment of sugarcane bagasse and straw with microwave irradiation in aqueous and acid glycerol solutions on their chemical composition, fiber structure and the efficiency of subsequent enzymatic hydrolysis. Thermogravimetric analysis showed that the pretreatment acted mainly on the lignin and hemicellulose fractions of the bagasse, whereas, in the straw, lesser structural and chemical changes were observed. The images from transmission electron microscopy (TEM) revealed that treating bagasse and straw with acid glycerol solution loosened the cell walls and there was a breakdown in the pit membrane. The treated material was submitted to hydrolysis for 72 h and higher yields of reducing sugars were observed compared to the untreated material (250.9 mg/g from straw and 197.4 mg/g from bagasse). TEM images after hydrolysis confirmed the possible points of access of the enzymes to the secondary cell wall region of the pretreated biomass. [ABSTRACT FROM AUTHOR]

Dehydration of glucose to 5-hydroxymethylfurfural (HMF) remains a significant problem in the context of the valorization of lignocellulosic biomass. Hydrolysis of WCl6 and NbCl5 leads to precipitation of Nb-containing tungstite (WO3⋅H2O) at low Nb content and mixtures of tungstite and niobic acid at higher Nb content. Tungstite is a promising catalyst for the dehydration of glucose to HMF. Compared with Nb2O5, fewer by-products are formed because of the low Brønsted acidity of the (mixed) oxides. In water, an optimum yield of HMF was obtained for Nb-W oxides with low Nb content owing to balanced Lewis and Brønsted acidity. In THF/water, the strong Lewis acidity and weak Brønsted acidity caused the reaction to proceed through isomerization to fructose and dehydration of fructose to a partially dehydrated intermediate, which was identified by LC-ESI-MS. The addition of HCl to the reaction mixture resulted in rapid dehydration of this intermediate to HMF. The HMF yield obtained in this way was approximately 56 % for all tungstite catalysts. Density functional theory calculations show that the Lewis acid centers on the tungstite surface can isomerize glucose into fructose. Substitution of W by Nb lowers the overall activation barrier for glucose isomerization by stabilizing the deprotonated glucose adsorbate. [ABSTRACT FROM AUTHOR]

The broadly apposite bioplastic, poly lactic acid was synthesized by using deinked paper waste as substrate, fermentation with Saccharomyces cerevisiae under controlled laboratory conditions followed by condensation polymerization. The substrate was initially subjected to acid hydrolysis followed by alkali neutralization to attain an ideal neutral pH for the growth of Saccharomyces cerevisiae. At regular intervals the amount of reducing sugar present in the samples were tested using 2,4-dinitrosalicyclic acid (DNS) method and the amount of sugar that was metabolized to alcohol and lactate were estimated using cerric ammonium nitrate and ρ-hydroxy biphenyl method respectively. The lactic acid extract was concentrated using a rotary vacuum evaporator and the amount was determined spectrophotometrically. The concentrated extract was used for polymerization in the presence of stannous chloride. This resulted in the production of white amorphous wafers. Polymerization trial with stannous chloride was done with 1 ml of purified extract with 0.1 g of stannous chloride. [ABSTRACT FROM AUTHOR]

The previous work on the hydrolysis and alcoholysis reactions of phosphonium ylides is summarized and reviewed in the context of their currently accepted mechanisms. Several experimental facts relating to ylide hydrolysis and to salt and ylide alcoholysis are shown to conflict with those mechanisms. In particular, we demonstrate that the p Ka values of water and alcohols are too high in organic media to bring about protonation of ylide. Therefore, we propose concerted addition of the water or alcohol O−H bond across the ylide P=C bond. In support of this, we provide NMR spectroscopic evidence for equilibrium between ylide and aclohol that does not require the involvement of phosphonium hydroxide. We report the first P-alkoxyphosphorane to be characterised by NMR spectroscopy that does not undergo exchange on an NMR timescale. Two-dimensional NMR spectroscopic techniques have been applied to the characterisation to P-alkoxyphosphoranes for the first time. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of plasma treatment on the surface of Ce 0.05 -Ni-W-B catalyst. The Ce 0.05 –Ni–W–B catalysts were treated with argon plasma at a different treatment time. Ce was used as a promoter. NaBH 4 concentration, NaOH concentration, temperature, plasma applying time and plasma gases was investigated for the hydrogen generation from the hydrolysis of NaBH 4 with Ce 0.05 -Ni-W-B catalyst. The catalysts were characterized using Fourier Transform Infrared spectrometry (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The results of the activity tests indicate that the plasma treatment greatly influence the activity. The activation energies for zero-order of the untreated and plasma treated Ce 0.05 -Ni-W-B catalysts were found to be 51.87 and 41.18 kJ mol −1 , respectively. [ABSTRACT FROM AUTHOR]

Background: The lignocellulose biorefinery based on the sugar platform usually focuses on polysaccharide bioconversion, while lignin is only burned for energy recovery. Pyrolysis can provide a novel route for the efficient utilization of residual lignin obtained from the enzymatic hydrolysis of lignocellulose. The pyrolysis characteristics of residual lignin are usually significantly affected by the pretreatment process because of structural alteration of lignin during pretreatment. In recent years, biological pretreatment using white-rot fungi has attracted extensive attention, but there are only few reports on thermal conversion of lignin derived from enzymatic hydrolysis residue (EHRL) of the bio-pretreated lignocellulose. Therefore, the study investigated the pyrolysis characteristics and kinetics of EHRL obtained from bamboo pretreated with Echinodontium taxodii in order to evaluate the potential of thermal conversion processes of EHRL. Results: Fourier transform infrared spectroscopy spectra showed that EHRL of bamboo treated with E. taxodii had the typical lignin structure, but aromatic skeletal carbon and side chain of lignin were partially altered by the fungus. Thermogravimetric analysis indicated that EHRL pyrolysis at different heating rates could be divided into two depolymerization stages and covered a wide temperature range from 500 to 900 K. The thermal decomposition reaction can be well described by two third-order reactions. The kinetics study indicated that the EHRL of bamboo treated with white-rot fungus had lower apparent activation energies, lower peak temperatures of pyrolysis reaction, and higher char residue than the EHRL of raw bamboo. Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) was applied to characterize the fast pyrolysis products of EHRL at 600 °C. The ratios of guaiacyl-type to syringyl-type derivatives yield (G/S) and guaiacyl-type to p-hydroxy-phenylpropane-type derivatives yield (G/H) for the treated sample were increased by 33.18 and 25.30 % in comparison with the raw bamboo, respectively. Conclusions: The structural alterations of lignin during pretreatment can decrease the thermal stability of EHRL from the bio-treated bamboo and concentrate the guaiacyl-type derivatives in the fast pyrolysis products. Thus, the pyrolysis can be a promising route for effective utilization of the enzymatic hydrolysis residue from bio-pretreated lignocellulose. [ABSTRACT FROM AUTHOR]

Phosphoroimidazolides play a critical role in several enzymatic phosphoryl transfer reactions and have been studied extensively as activated monomers for nonenzymatic nucleic acid replication, but the detailed mechanisms of these phosphoryl transfer reactions remain elusive. Some aspects of the mechanism can be deduced by studying the hydrolysis reaction, a simpler system that is amenable to a thorough mechanistic treatment. Here we characterize the transition state of phosphoroimidazolide hydrolysis by kinetic isotope effect (KIE) and linear free energy relationship (LFER) measurements, and theoretical calculations. The KIE and LFER observations are best explained by calculated loose transition structures with extensive scissile bond cleavage. These three-dimensional models of the transition state provide the basis for future mechanistic investigations of phosphoroimidazolide reactions. [ABSTRACT FROM AUTHOR]

The content and speciation of heavy metals can fundamentally affect the hydrolysis of sludge. This research study investigates the migration and transformation rule of heavy metals during the hydrolysis process by measuring the content of exchangeables (F1), bound to carbonates (F2), bound to Fe-Mn oxides (F3), bound to organic matter (F4), and residuals (F5) under different periods of time undergoing hydrolysis. The results show that the hydrolysis process generally stabilized Cu, Zn, Mn, Ni, Pb, Cr, and As by transforming the unstable states into structurally stable states. Such transformations and stabilization were primarily caused by the changes in local metal ion environment and bonding structure, oxidation of sulfides, pyrolyzation of organic matter, and evaporation of resulting volatile materials. An X-ray diffractometry (XRD) of the residuals conducted after hydrolysis indicated that hydrolysis did have a significant influence on the transportation and transformation of heavy metals. [ABSTRACT FROM AUTHOR]

The biomimetic nature of micellar catalysis can significantly affect the rate of chemical reactions due to the effects of concentration and the change of microenvironment. Here, a key role is played by the nature of the head group. The catalytic activity of alkyltriphenylphosphonium bromides (TPPB- n ; n = 10, 12, 14, 16, 18; n is the number of carbon atoms in alkyl groups) in the nucleophilic substitution of p -nitrophenyl esters of alkylchloromethylphosphonic acid were investigated by the method of spectrophotometry. Using pyrene, prodan and Sudan I as probes the values of critical micelle concentrations and aggregation numbers were determined. A comparison of the results of kinetic dependence processing by Berezin equation obtained for TPPB series with the known ammonium analogues was carried out. It was found that for TPPB- n series, the higher acceleration of reaction has been achieved due to concentration factor compared to ammonium surfactants. This agrees with the fact that alkyltriphenylphosphonium bromides demonstrate higher aggregation activity forming micelles with higher solubilizing capacity. [ABSTRACT FROM AUTHOR]

An alkaline pretreatment was performed on hardwood elm to improve enzymatic hydrolysis and ethanol production. The pretreatment was conducted with 8% (w/v) NaOH solution at 0, 25, and 80 °C for 2 h, and the best results were obtained by the pretreatment at 0 °C. The glucose yield from untreated wood was only 8.0% and improved to 71.5% after the pretreatment at 0 °C, whereas the corresponding ethanol yield was improved from 11.1% to 45.7%. In order to decrease ineffective adsorption of cellulase enzyme on lignin and enhance the enzymatic hydrolysis and fermentation yields, a non-ionic surfactant, Tween-20, was used in the hydrolysis process. The addition of 2.5 g L −1 Tween-20 further favorably modified the yields of enzymatic hydrolysis and ethanol production to 79.8% and 57.3%, respectively. Changes in the wood’s structural properties by the pretreatment were followed in detail by swelling and buffering capacity measurements as well as SEM and FTIR analyses. Furthermore, the adsorption and desorption of cellulase during the enzymatic hydrolysis were investigated, and a consistent relation was observed between adsorbed and desorbed enzymes and enzymatic hydrolysis yield. [ABSTRACT FROM AUTHOR]

Summary p97 belongs to the superfamily of AAA+ ATPases and is characterized by a tandem AAA module, an N-terminal domain involved in substrate and cofactor interactions, and a functionally important unstructured C-terminal tail. The ATPase activity is controlled by an intradomain communication within the same protomer and an interdomain communication between neighboring protomers. Here, we present for the first time crystal structures in which the physiologically relevant p97 hexamer constitutes the content of the asymmetric unit, namely in the apo state without nucleotide in either the D1 or D2 module and in the pre-activated state with ATPγS bound to both modules. The structures provide new mechanistic insights into the interdomain communication mediated by conformational changes of the C terminus as well as an intersubunit signaling network, which couples the nucleotide state to the conformation of the central putative substrate binding pore. [ABSTRACT FROM AUTHOR]

Cleavage of ester bonds by extracellular microbial hydrolases is considered a key step during the breakdown of biodegradable polyester materials in natural and engineered systems. Here we present a novel analytical approach for simultaneous detection of changes in the masses and rigidities of polyester thin films during enzymatic hydrolysis using a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D). In experiments with poly(butylene succinate) (PBS) and the lipase of Rhizopus oryzae (RoL), we detected complete hydrolysis of PBS thin films at pH 5 and 40 °C that proceeded through soft and water-rich film intermediates. Increasing the temperature from 20 to 40 °C resulted in a larger increase of the enzymatic hydrolysis rate of PBS than of nonpolymeric dibutyl adipate. This finding was ascribed to elevated accessibility of ester bonds to the catalytic site of RoL due to increasing polyester chain mobility. When the pH of the solution was changed from 5 to 7, initial hydrolysis rates were little affected, while a softer film intermediate that lead to incomplete film hydrolysis was formed. Hydrolysis dynamics of PBS, poly(butylene adipate), poly(lactic acid), and poly(ethylene terephthalate) in assays with RoL showed distinct differences that we attribute to differences in the polyester structure. [ABSTRACT FROM AUTHOR]

This experiment used the hydrolysis reaction of silicon tetrachloride to produce highly dispersed silica. The particles’ tendency towards agglomeration was significantly reduced by adding octane and ethanol to the silicon tetrachloride hydrolysis system, as they decreased the permittivity of the reaction system and reduced the hydrogen–bond interaction. The effects of varying amounts of ethanol, octane, and water were investigated. As the ratio of water rose, the particle size decreased and the surface area increased. Ethanol significantly improved the dispersion of the nanosilica and also affected the shape of the particles. The addition of octane to the reaction system decreased the particle size and increased the surface area. This system produced highly dispersed silica precipitates with surface areas of 100–300 m 2 /g and pore volumes of 0.06–0.3 cm 3 /g. The findings will be of great importance in the preparation of highly dispersed silica and contribute to the understanding of the hydrolysis of silicon tetrachloride. [ABSTRACT FROM AUTHOR]

The present study aims to optimize the enzymatic hydrolysis condition and determine the functional properties of eel (Monopterus albus) protein hydrolysate (EPH) at different hydrolysate concentrations (0.1%, 0.5%, 1.0%). The enzymatic hydrolysis (using alcalase) condition; namely, temperature (°C), enzyme to substrate concentration (%) and pH on both the yield and degree of hydrolysis (DH), as responses, was optimized using the response surface methodology (RSM) by employing three factors, 3-level, Central Composite Design (CCD). The optimum hydrolysis condition suggested was a temperature of 55.76 °C, enzyme concentration of 1.80% and pH of 9. The experimental result for yield (9.45%) was higher while the experimental result for DH (15.01%) was lower than the predicted values of the responses using the quadratic model, which were 5.67% and 16.73%, respectively. The findings for the functional properties showed that the Nitrogen Solubility Index (NSI) of EPH was 85%. The emulsion stability index (ESI) of EPH was shown to decrease with the increase hydrolysate concentration (0.1%, 0.5%, 1.0%) while the foam expansion of EPH showed an increase with the increase in concentration. High solubility and the ability of EPH to emulsify and form foam show its potential for use as a natural binding and emulsifying agent. [ABSTRACT FROM AUTHOR]