Excellent Thermostability Research Articles

Both Phosphonic Acid- and Fluorine-Containing Poly(aryl ether)-hydroxyapatite Biocomposites: Toward Enhanced Biocompatibility and Bonelike Elastic Modulus.

Metal-based implants possess excellent mechanical strength, corrosion resistance, and biocompatibility and can deliver favorable performances in clinic treatments. However, modulus mismatching is considered a common defect for metal-based materials, while polymer-based materials with a bonelike elastic modulus have been regarded as one of the most promising candidates for bone replacement implants. In this work, a phosphonic acid- and fluorine-containing poly(aryl ether) (PAE) resin is designed and synthesized, which is determined to be an amorphous polymer with excellent thermostability. The elastic modulus of composites is improved to 15.7 GPa by reinforcing with 60 wt % hydroxyapatite (HA), which demonstrates admirable protein adsorption and hydrophilicity. After 14 days of immersion in simulated body fluid, a layer of HA deposition can be observed, indicating favorable bioactivity in advance, and the preliminary in vitro cell experiments also suggest that PAE-HA composites possess favorable cell responses on adhesion, proliferation, and differentiation, which reveal the feasibility of synthesized polymers to be employed as bone replacement materials, while the adjustability in molecular chains also leaves room for further investigations.

Silver nanoparticles immobilized on cellulose nanofibrils for starch-based nanocomposites with high antibacterial, biocompatible, and mechanical properties

We describe an effective method to create nanocomposites of silver nanoparticles that were stabilized by cellulose nanofibrils (CNF-AgNPs) that were then mixed with a starch matrix. The incorporation of CNF-AgNPs nanocomposites significantly enhanced the mechanical and antibacterial properties of hybrid films. The starch-based films with only 5.0 wt% CNF-AgNPs content exhibited superior mechanical properties in which the Young’s modulus increased from 80.3 to 381.5 MPa and tensile strength increased from 6.06 to 9.96 MPa at 50% RH. Taking advantage of the denser microstructure and strong interfibrillar networks, the nanocomposite film can resist more external tensile forces and show excellent barrier property and thermostability. Moreover, antibacterial analysis indicated that CNF-AgNPs/starch nanocomposite films exhibited strong bactericidal effects against representative both Escherichia coli and Staphylococcus aureus. The cell viability of 87.71% and clear morphologies of live cells implied good biocompatibility of nanocomposite films. The demonstrated characteristics of CNF-AgNPs/starch nanocomposite film verified its suitability as a sustainable material for food packaging.

Blue low-threshold room-temperature stimulated emission from thermostable perovskite nanocrystals glasses through controlling crystallization

Perovskite nanocrystals (NCs) can achieve blue stimulated emission readily by the halide stoichiometry mixing method compared with the traditional metal chalcogenide NCs. However, most perovskite materials can obtain stimulated emission only at low temperatures because nonradiative recombination associated with defects predominates at room temperature. Here, by adjusting the composition and controlling crystallization, a series of CsPbClxBr3−x NCs glasses with large particle size were prepared by traditional melt-quenching to overcome the obstacles, which demonstrated low-threshold stimulated emission from blue to cyan (blue: ∼1.02–0.55 mJ/cm2, cyan: ∼1.59–1.34 mJ/cm2) under two-photon excitation at room temperature. And the CsPbClxBr3-x NCs glasses showed excellent thermostability, which suggested a new opportunity for ultra-stable nonlinear photonics and lasers.

Enhancing the Thermostability of Papain by Immobilizing on Deep Eutectic Solvents-Treated Chitosan With Optimal Microporous Structure and Catalytic Microenvironment.

Deep eutectic solvents (DESs) have attracted an increasing attention in the fields of biocatalysis and biopolymer processing. In this study, papain immobilized on choline chloride- lactic acid (ChCl-Lac) DES-treated chitosan exhibited excellent thermostability as compared to the free enzyme. The properties of native or DES-treated chitosan and immobilized enzyme were characterized by FT-IR, SEM, surface area and pore property analysis. Like the common enzyme immobilization, papain immobilized on DES-treated chitosan resulted in a lower catalytic efficiency and a higher thermostability than the free enzyme due to the restricted diffusion. The results also revealed that DES could control the active group content, thus achieving the appropriate microporous structure of immobilized enzyme. Meanwhile, it could also help to construct the optimal microenvironment by hydrogen-bonding interaction between enzyme, chitosan, and residual DES, which are benefit for maintaining an active conformation and subsequently a high thermostability of papain. Moreover, it was found that trace DES (10 mM) significantly promoted the activity of free papain (145%). Deactivation thermodynamics study showed that the DES could enhance the thermostability of papain especially at high temperature (half-life of 7.4 vs. 3.5 h) because of the increased Gibbs free energy of denaturation. Secondary structure analysis by circular dichroism spectroscopy (CD) agreed well with the activity and thermostability data, further confirming the formation of rigid conformation induced by a specific amount of DES. This work provides a new way of enzyme immobilization synergistically intensified by solvents and supporting materials to achieve better microporous structure and catalytic microenvironment.

High conductivity and alkali-resistant stability of imidazole side chain crosslinked anion exchange membrane

Poly (aryl ether ketone) polymers (PAEKS) were synthesized by polycondensation of trimethyl hydroquinone, allyl bisphenol S and 4,4-difluorodiphenyl ketone as monomers. A series of uncrosslinked and crosslinked anion exchange membranes (AEMs) with diverse contents of 1-allyl-3-methylimidazolium chloride and 1-vinylimidazole were prepared by grafting and bromination reaction. The 1-vinylimidazole in the AEMs was simultaneously present as a crosslinked agent. 1HNMR and FT-IR spectra demonstrated the structure of the above PAEKS and AEMs, respectively. TEM images and SAXS profiles showed the formation of distinct hydrophilic/hydrophobic microphase separation in the TCImP membranes, which offered vast of channels for ion transmission. Among them, TCImP-3 membrane showed the highest hydroxide conductivity of 0.144 S/cm at 80 °C. Compared with the uncrosslinked AEMs, the crosslinked AEMs exhibited slightly lower water uptake and swelling ratio. The crosslinked structures in the AEMs were helpful to improve the mechanical property and alkali-resistant stability of AEMs. The hydroxide conductivity of the TCImP-3 membrane kept 0.117 S/cm in 2 M NaOH solutions at 80 °C for 400 h. Meanwhile, crosslinked AEMs showed excellent thermostability. We believe that TCImP membranes are a promising AEMs material.

Novel energetic coordination compounds based on 3,5-dinitro-4-oxylpyrazolate ligand with excellent thermostability and low sensitivity

In recent years, the discovery of novel energetic coordination compounds (ECCs) with high energy performance and low sensitivity is very desirable but highly challenging. Nitroazole-based ECCs have attracted a lot of attention in this area owing to their prominent advantages including excellent energy performance and good thermostability. Herein, three new ECCs based on 3,5-dinitro-4-oxylpyrazolate (DNOP) ligand were synthesized, characterized and evaluated as potential high-energy materials. Their structures and coordination mode were confirmed by the single crystal X-ray diffraction analysis. Thermal stability, sensitivities and energy performance were measured and studied in detail. The results suggest that as-prepared new ECCs are classified as “less sensitive” energetic materials exhibiting relative low sensitivity (IS = 14–18 J, FS = 240–324 N). Additionally, these new ECCs exhibit excellent thermal stability with high decomposition temperature beyond 290 °C. Inheriting the significant energy performance of 3,5-dinitro-4-oxylpyrazolate ligand, they could also possess attractive energy property.

Interfacial Structure and Composition Managements for High‐Performance Methylammonium‐Free Perovskite Solar Cells

AbstractThe methylammonium (MA)‐free perovskite solar cells (PSCs) have drawn broad attention due to their excellent thermostability. However, the efficiency of these devices is inferior to most state‐of‐the‐art PSCs. Herein, the photovoltaic performance of the MA‐free PSCs is enhanced by constructing interfacial capping layers with a pair of alkylammonium halides, n‐propylammonium (PA) iodide and propane‐1,3‐diammonium (PDA) iodide. The structure and composition of the interfacial layers are comprehensively investigated and their correlation with the device performance is presented in terms of defect passivation efficacy, energy level alignment, and hydrophobicity for moisture resistance. The PSC devices based on the PAI and PDAI2 treated MA‐free perovskite films demonstrate better power conversion efficiencies (PCEs) and stabilities than the reference devices without the interfacial layers. Although the PAI‐treated devices exhibit the highest PCE of 21.1%, the PDAI2‐treated PSCs demonstrate the exceptional thermal and humidity stabilities.

Conformational and Compositional Tuning of Phenanthrocarbazole-Based Dopant-Free Hole-Transport Polymers Boosting the Performance of Perovskite Solar Cells.

Conjugated polymers are regarded as promising candidates for dopant-free hole-transport materials (HTMs) in efficient and stable perovskite solar cells (PSCs). Thus far, the vast majority of polymeric HTMs feature structurally complicated benzo[1,2-b:4,5-b’]dithiophene (BDT) analogs and electron-withdrawing heterocycles, forming a strong donor–acceptor (D–A) structure. Herein, a new class of phenanthrocarbazole (PC)-based polymeric HTMs (PC1, PC2, and PC3) has been synthesized by inserting a PC unit into a polymeric thiophene or selenophene chain with the aim of enhancing the π–π stacking of adjacent polymer chains and also to efficiently interact with the perovskite surface through the broad and planar conjugated backbone of the PC. Suitable energy levels, excellent thermostability, and humidity resistivity together with remarkable photoelectric properties are obtained via meticulously tuning the conformation and elemental composition of the polymers. As a result, PSCs containing PC3 as dopant-free HTM show a stabilized power conversion efficiency (PCE) of 20.8% and significantly enhanced longevity, rendering one of the best types of PSCs based on dopant-free HTMs. Subsequent experimental and theoretical studies reveal that the planar conformation of the polymers contributes to an ordered and face-on stacking of the polymer chains. Furthermore, introduction of the “Lewis soft” selenium atom can passivate surface trap sites of perovskite films by Pb–Se interaction and facilitate the interfacial charge separation significantly. This work reveals the guiding principles for rational design of dopant-free polymeric HTMs and also inspires rational exploration of small molecular HTMs.

A hybrid gel polymer electrolyte with imide groups modified by the coupling agent and its application in electrochromic devices

Herein, a new class of hybrid gel polyelectrolytes (GPEs) through sol–gel technology has been synthesized and characterized. The reaction mechanism of gel polymer electrolyte is based on the hydrosilylation and sol–gel reactions of poly(propylene glycol) bis(2-aminopropyl ether), pyromellitic dianhydride, glycidoxypropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane. The gel polymer electrolyte exhibits excellent ion-conductive and thermostability performance. The maximum ionic conductivity value of 3.1 × 10−4 S cm−1 and Li-ion transference numbers (t+) reaching 0.49 at 25 °C are achieved for the gel polymer electrolyte. The thermogravimetric analysis results show that the electrolyte samples are nearly 1% weight loss when the temperature reaches up to 100 °C. The gel polymer electrolytes display a prominent electrochemical stability, which could bear potential up to 10 V. In addition, the prototype electrochromic device using electrolyte sample as the conductive layer presents excellent coloration efficiency of 198.9 cm2 C−1, stable cycle of 125 periods under 5-V high-voltage environment, and stable cycling performance (achieving 300 stable cycles from the voltage of −3.5 to 2.5 V). As a result, the GPEs exhibit an excellent electrochemical performance, which is suitable for electrochromic application and offers a remarkable prospective.

Three-dimensional homochiral coordination polymers of Eu(III) and Tb(III): Synthesis, structure determination, and optical properties

Self-assembly of the corresponding europium and terbium salts with designed chiral ligand (S)-5-((2-carboxy-5-oxopyrrolidin-1-yl)methyl)isophthalic acid (H3L) generated two novel 3D coordination polymers {[Eu(L)]·0.5CH3CN}n (1) and {[Tb(L)]·0.5CH3CN}n (2). Single-crystal X-ray diffraction analyses reveal that 1 and 2 are isostructural metal-organic frameworks built from four-stranded helixes. Complexes 1 and 2 are intriguing homochiral porous architectures with 6,6-connected (48∙66∙8)(413∙62) topology, whose homochirality was further confirmed by their solid-state circular dichroism spectra. Thermal analyses disclose that the desolvated frameworks of 1 and 2 can maintain their structural stability below 370 ​°C. Solid-state photoluminescence studies show that 1 and 2 exhibit strong characteristic Eu(III) and Tb(III) emissions with long lifetimes of 1.31 and 1.35 ​ms, respectively. In addition, 1 and 2 also exhibit significant second harmonic generation activities with their intensities of about 0.29 and 0.31 times larger than that of potassium dihydrogenphosphate, respectively. Very importantly, the excellent thermostabilities and strong red and green emissions of 1 and 2 are of great significance for further exploration of their applications in optical devices.

Combined Proteome and Transcriptome Analysis of Heat-Primed Azalea Reveals New Insights Into Plant Heat Acclimation Memory.

Plants can obtain superinduction of defense against unpredictable challenges based on prior acclimation, but the mechanisms involved in the acclimation memory are little known. The objective of this study was to characterize mechanisms of heat acclimation memory in Rhododendron hainanense, a thermotolerant wild species of azalea. Pretreatment of a 2-d recovery (25/18°C, day/night) after heat acclimation (37°C, 1 h) (AR-pt) did not weaken but enhanced acquired thermotolerance in R. hainanense with less damaged phenotype, net photosynthetic rate, and membrane stability than non-acclimation pretreated (NA-pt) plants. Combined transcriptome and proteome analysis revealed that a lot of heat-responsive genes still maintained high protein abundance rather than transcript level after the 2-d recovery. Photosynthesis-related genes were highly enriched and most decreased under heat stress (HS: 42°C, 1 h) with a less degree in AR-pt plants compared to NA-pt. Sustainably accumulated chloroplast-localized heat shock proteins (HSPs), Rubisco activase 1 (RCA1), beta-subunit of chaperonin-60 (CPN60β), and plastid transcriptionally active chromosome 5 (pTAC5) in the recovery period probably provided equipped protection of AR-pt plants against the subsequent HS, with less damaged photochemical efficiency and chloroplast structure. In addition, significant higher levels of RCA1 transcripts in AR-pt compared to NA-pt plants in early stage of HS showed a more important role of RCA1 than other chaperonins in heat acclimation memory. The novel heat-induced RCA1, rather than constitutively expressed RCA2 and RCA3, showed excellent thermostability after long-term HS (LHS: 42/35°C, 7 d) and maintained balanced Rubisco activation state in photosynthetic acclimation. This study provides new insights into plant heat acclimation memory and indicates candidate genes for genetic modification and molecular breeding in thermotolerance improvement.

Giant Enhancement of Fluorescence Emission by Fluorination of Porous Graphene with High Defect Density and Subsequent Application as Fe3+ Ion Sensors.

Defect-mediated nonradiative recombination in traditional semiconductors, such as porous graphene, tremendously lowers the fluorescence emission, thus greatly restricting their applications in more extensive fields. Here, we report that the fluorescence emission of porous graphene with a high defect density has a giant enhancement (about two orders of magnitude) by a direct and simple fluorination strategy, showing a fine defect-tolerance characteristic. Meanwhile, the corresponding fluorocarbon bonds with excellent thermostability (over 500 °C in N2 even air) also bring about good stability. The photophysical origins during the whole photoluminescence evolution are further investigated. In the excitation process, the coexistence of fluorine and aromatic regions in fluorinated porous graphene (FPG) contributes to producing a new electronic band gap structure to match the maximum excitation wavelength, then numerous excitons generate, which is a precondition for strong fluorescence emission. In the emission process, weak electron-phonon interactions, large rigidity, and constrained electron at the defects in FPG greatly reduce nonradiative recombination loss. Moreover, fluorine at the defects also reduces interlayer interactions among FPG nanosheets and resists the influence of absorbed impurities, thereby further restricting nonradiative recombination pathway. Highly fluorescent FPG has been utilized as a fascinating tool to achieve sensitive and naked-eye detection of Fe3+ ions with a high selectivity. The fluorescence quenching efficiency reaches 24% even with an ultralow concentration of Fe3+ (0.06 μM), and that increases to 84% when the concentration of Fe3+ is 396 μM.

Renewable and robust biomass carbon aerogel derived from deep eutectic solvents modified cellulose nanofiber under a low carbonization temperature for oil-water separation

Carbon aerogels are potential materials in oil/water separation. However, the key challenges of the scare/toxic precursor, metals employment, unsatisfied reuse, and high calcination temperature still remain. Here, we fabricated a novel, robust and hydrophobic carbon aerogel (DCCA-350) derived from deep eutectic solvents (DESs, formed by glucose and choline chloride) modified cellulose nanofiber (CNF) under low carbonization temperature of 350 °C. The raw materials are renewable and abundant, and the as-prepared carbon aerogel possesses the high volume absorption capability for organic pollutants and oils range from 74% to 95%. Due to its excellent thermostability and mechanical properties, methods of combustion and distillation can be applied for the recycling of the DCCA-350 carbon aerogel up to 100 cycles. The effective oils/water separation is mainly attributed to the presence of roughness surface and reduced hydrophilic groups in the carbon aerogel. This is also the first development of carbon aerogel derived from DESs modified CNF, with a promising application on oil/water separation.

Noncovalent π-stacked robust topological organic framework

Organic frameworks (OFs) offer a novel strategy for assembling organic semiconductors into robust networks that facilitate transport, especially the covalent organic frameworks (COFs). However, poor electrical conductivity through covalent bonds and insolubility of COFs limit their practical applications in organic electronics. It is known that the two-dimensional intralayer π∙∙∙π transfer dominates transport in organic semiconductors. However, because of extremely labile inherent features of noncovalent π∙∙∙π interaction, direct construction of robust frameworks via noncovalent π∙∙∙π interaction is a difficult task. Toward this goal, we report a robust noncovalent π∙∙∙π interaction-stacked organic framework, namely πOF, consisting of a permanent three-dimensional porous structure that is held together by pure intralayer noncovalent π∙∙∙π interactions. The elaborate porous structure, with a 1.69-nm supramaximal micropore, is composed of fully conjugated rigid aromatic tetragonal-disphenoid-shaped molecules with four identical platforms. πOF shows excellent thermostability and high recyclability and exhibits self-healing properties by which the parent porosity is recovered upon solvent annealing at room temperature. Taking advantage of the long-range π∙∙∙π interaction, we demonstrate remarkable transport properties of πOF in an organic-field-effect transistor, and the mobility displays relative superiority over the traditional COFs. These promising results position πOF in a direction toward porous and yet conductive materials for high-performance organic electronics.

Rapid Room-Temperature Preparation of Hierarchically Porous Metal-Organic Frameworks for Efficient Uranium Removal from Aqueous Solutions.

The effective removal of uranium from an aqueous solution is a highly valuable process for the environment and health. In this study, we developed a facile and rapid method to synthesize hierarchically porous Cu-BTC (RT-Cu-BTC) using a cooperative template strategy. The as-synthesized RT-Cu-BTC exhibited hierarchically porous structure and excellent thermostability, as revealed by X-ray powder diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Compared with conventional metal–organic frameworks (MOFs) and zeolites, the obtained RT-Cu-BTC exhibited enhanced adsorption capacity (839.7 mg·g−1) and high removal efficiency (99.8%) in the capture of uranium (VI) from aqueous solutions. Furthermore, the conditions such as adsorbent dose, contact time, and temperature in adsorption of uranium (VI) by RT-Cu-BTC were investigated in detail. The thermodynamics data demonstrated the spontaneous and endothermic nature of the uranium (VI) adsorption process. The Langmuir isotherm and pseudo-second-order models could better reflect the adsorption process of uranium (VI) onto RT-Cu-BTC. In addition, the as-synthesized RT-Cu-BTC showed excellent stability in removing uranium (VI) from an aqueous solution. This work provides a facile and rapid approach for fabricating hierarchically porous MOFs to realize a highly efficient removal of uranium (VI) from aqueous systems.

Expression and characterization of l-arabinose isomerase from Geobacillus stearothermophilus for improved activity under acidic condition

A low-calorie sugar-substituting sweetener, d-tagatose, can be produced by l-arabinose isomerase (l-AI) from the substrate d-galactose. However, this process suffers from a Maillard reaction when performed at alkaline pH and high temperature. For industrial applications, therefore, a reaction under slightly acidic conditions is desirable to minimize the Maillard reaction. Previously, we obtained a mutant of l-AI, H18T, from Geobacillus stearothermophilus with greater substrate specificity. Although H18T possessed excellent thermostability, its activity under acidic conditions was not optimal. Here, we successfully obtained a potential variant of the H18T protein, H18T-Y234C, which achieved improved activity at pH 6.0, based on random mutagenesis using error-prone PCR around the binding pocket area of H18T. This double H18T-Y234C mutant possessed 1.8-fold and 3-fold higher activity at pH 6.0 than the parent H18T and the wild type, thereby broadening the optimal pH range to 6.0–8.0. Mutation from Tyr to Cys at residue 234 had little effect on the secondary structure of L-AI. Furthermore, the formation of disulfide bonds was not detected. Thus, the improvement of activity at pH 6.0 is probably caused by the change in the binding pocket area involving residue 234. This study offers insight into the importance of residue 234 in improving the activity under acidic conditions.

Synthesis and properties of waterborne UV‐curable polydimethylsiloxane‐based polyurethane oligomers: UV‐cured film with excellent water resistance and thermostability

This paper designed and synthesized a series of waterborne UV-curable polydimethylsiloxane‐based polyurethane oligomers which contain polydimethylsiloxane segment in the end of the main chain, a plurality of double bonds in the side chain and two kinds of hydrophilic groups including nonionic polyethylene glycol with low molecular weight and ionic quaternary ammonium salt groups. The unique structure endowed not only the oligomer with an excellent water solubility, but also the UV-cured film with hydrophobicity, thermostability and mechanical properties. The prepared oligomers could form a stable white emulsion and had excellent photopolymerization capability, and their conversions of double bonds were all over 92%. The UV-cured film containing long chain polydimethylsiloxane exhibited better hydrophobicity, heat resistance and tensile strength. The polydimethylsiloxane segment located in the end of the oligomer molecular chain was more conducive to its enrichment in the surface of the cured films and improving of the hydrophobicity of the cured films. The water absorption, surface water contact angle and the initial decomposition temperature (T5%) of the obtained UV-cured films were 2.7%, 91 and 301 °C, respectively.

Coupled acid and base UiO-66-type MOFs supported on g-C3N4 as a bi-functional catalyst for one-pot production of 5-HMF from glucose

Abstract Chemically functional microporous metal-organic frameworks (MOFs) crystals are attractive for catalysis applications, and recent results show that they can be immobilized on high stability substrates, such as carbon materials. In this work, g-C3N4 supported UiO-66-type MOFs catalysts with only acid, base or acid-base bi-functional active sites, have been successfully synthesized via a green (aqueous solutions), mild (90 °C, atmospheric pressure), and one-pot modulated hydrothermal (MHT) method. The physical and chemical properties of the obtained catalysts were systematically characterized by different characterization methods. The results indicated that the synthesized catalysts have microporous structure, excellent thermostability and acid-base bi-functional active sites. One-pot synthesis of 5-hydroxymethylfurfural (5-HMF) from glucose was performed to investigate the activities of synthesized catalysts. Benefiting from the synergistic effects of the acid-base bi-functional active sites, the highest 5-HMF yield of 54.9% was achieved in an isopropanol-mediated DMSO system, under the optimal conditions. Moderate to excellent yields of 5-HMF were also obtained from one-pot conversions of other carbohydrates, including inulin, sucrose, cellobiose, maltose and starch, with our developed catalytic system. The one-pot production of 5-HMF from cellulose was also smoothly processed by the g-C3N4 supported UiO-66-type MOFs catalysts in an IL-based system. This work offers a versatile strategy for developing supported UiO-66-type MOFs catalyst for a wide range of biomass transformation to platform chemicals.

Preparation and Properties of Capric–Myristic Acid/Expanded Graphite Composite Phase Change Materials for Latent Heat Thermal Energy Storage

A novel composite phase change material (CPCM), capric–myristic acid/expanded graphite (CA–MA/EG) CPCM, was prepared by absorbing liquid CA–MA (as the phase change material (PCM)) into EG (as the substrate material) for heat storage in the backfill materials of soil-source heat pump systems. The thermal characteristics and microstructure of the novel CPCM were analyzed using differential scanning calorimetry (DSC) and scanning electronic microscopy (SEM). The thermal conductivities of CA–MA/EG CPCM were surveyed. The thermal stability of the CA–MA/EG was analyzed using thermogravimetric analysis (TGA) and thermal cycle tests. The results showed that the optimal mass content of CA–MA in CPCM was approximately 92.4% and the CA–MA was uniformly distributed in the vesicular structure of EG; the CA–MA/EG CPCM had an appropriate phase change temperature (Tm: 19.78 °C, Tf: 18.85 °C), high latent heat (Hm: 137.3 J/g, Hf: 139.9 J/g), and excellent thermostability and thermal reliability. The thermal conductivity of the CPCM was remarkably enhanced after adding EG. Therefore, the CPCMs demonstrated outstanding thermal performance and can be utilized in low-temperature latent heat thermal energy storage (LHTES) systems, such as soil-source heat pump systems.

Purification and characterization of a novel β-glucuronidase precisely converts glycyrrhizin to glycyrrhetinic acid 3-O-mono-β-D-glucuronide from plant endophytic Chaetomium globosum DX-THS3

Glycyrrhetinic acid monoglucuronide (GAMG) is an innovative functional sweetener with higher sweetness and stronger pharmacological activity than glycyrrhizin (GL). A novel β-glucuronidase (cg-GUS) was firstly screened from plant endophytic fungus Chaetomium globosum DX-THS3. The cg-GUS demonstrated the specify and highly transform glycyrrhizin (GL) to generate GAMG, and the maximum activity of β-glucuronidase at 45 °C and pH 6.0, displaying excellent thermostability and pH-stability. The Km and Vmax values of cg-GUS were 0.134 mM and 236.42 mM/min/mg, respectively, which showed the high chemical bond selectivity and biotransformation efficiency of cg-GUS. Meanwhile, the cg-GUS gene (1896 bp) was analyzed, and Gly-345, Ser-539, Gly-563, Ala-579, Ser-581 and Glu-619 in GH2 catalytic domain of cg-GUS are potential mutation position for result in high-efficient and substrate-specify of cg-GUS. Our results were indicated that cg-GUS is a biocatalyst for production of GAMG and potent application in food and medicinal industry.