Covalent organic networks for in situ entrapment of enzymes with superior robustness and durability

Enzyme-based nanobiohybrids (EnNBHs) are an emerging biocatalyst family that can manufacture industrial products such as fuels and chemicals in a green and low- carbon manner. Designing high-performance EnNBHs could confer enzymes with superior robustness and durability, while current strategies confront grand challenges. Indeed, the reticular chemistry materials, especially metal-organic frameworks (MOFs), covalent organic frameworks (COFs), hydrogen-bond organic frameworks (HOFs), are several good candidates for constructing EnNBHs. While, MOFs and HOFs are constructed by coordination bond and hydrogen bond, respectively, which may be destroyed by acid or organic solvents, thus causing structural degradation and loss of protection to enzymes. The use of acetic acid (6 mol L-1) and organic solvents is conventional conditions for the synthesis of COFs, which may be inapplicable for de novo constructing EnNBHs. Herein, a facile and versatile in situ entrapment strategy is developed to entrap a series of enzymes in crystalline imine-based covalent organic networks (CONs) under mild conditions. Notably, the growth rate of CONs induced by glucose oxidase (GOx) is increased by 2 folds than that of CONs in the absence of GOx. Moreover, the crystalline CONs could create confinement environment and safeguard the hosted enzymes from being denatured under unfavorable conditions. Given moderate crystallinity of CONs, short-range ordered micro/meso-porous structures are generated. Compared with GOx@ZIFs, the larger transport channels for reactants/products in GOx@CONs result in 1.73-fold enhancement in the catalytic efficiency. The crystalline CONs could also serve as a cell-mimic nanoreactor for multienzyme catalysis, demonstrating the potential applications in biomanufacturing, bioimaging, biosensing and so on

Catalytic roles of Mo-based sites on MoS2 for ethanolysis of enzymatic hydrolysis lignin into aromatic monomers

| openaire: EC/H2020/101006744/EU//EHLCATHOL Funding Information: This work is supported by the National Natural Science Foundation of China (21808163 and 21690083). This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101006744. The content presented in this document represents the views of the authors, and the European Commission has no liability in respect of the content. Funding Information: This work is supported by the National Natural Science Foundation of China ( 21808163 and 21690083 ). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101006744 . The content presented in this document represents the views of the authors, and the European Commission has no liability in respect of the content. Publisher Copyright: © 2022 The AuthorsThe depolymerization of enzymatic hydrolysis lignin (EHL) is examined over one-step hydrothermal-synthesized MoS2 in ethanol without hydrogen gas. Value-added aromatic molecules, mainly including alkyl-substituted phenols (A-Ps), are obtained without char or tar formation. The MoS2 samples prepared with different Mo and S precursors have been tested and the highest aromatic monomer yield of 226.4 mg/g EHL is achieved over the MoS2 prepared with thioacetamide and sodium molybdate as precursors (STA-MoS2) at 320 °C for 12 h. Proper ratios of Mo6+/Mo5+ (~0.46–0.65) and (Mo6++Mo5+)/Mo4+ (~0.47–0.62) on the surface of MoS2 catalysts are found to be significant for the achievement of high overall aromatic monomer yield. MoOxSy species with Mo5+ and S22- is proposed as the active site for the production of complex alkyl phenols via demethoxylation and alkylation. The carbon deposition and the exchanges of sulfur and oxygen atoms resulted from the oxidization are likely responsible for the deactivation of catalyst.Peer reviewe

Methylglyoxal Induces Systemic Symptoms of Irritable Bowel Syndrome

<div><p>Patients with irritable bowel syndrome (IBS) show a wide range of symptoms including diarrhea, abdominal pain, changes in bowel habits, nausea, vomiting, headache, anxiety, depression and cognitive impairment. Methylglyoxal has been proved to be a potential toxic metabolite produced by intestinal bacteria. The present study was aimed at investigating the correlation between methylglyoxal and irritable bowel syndrome. Rats were treated with an enema infusion of methylglyoxal. Fecal water content, visceral sensitivity, behavioral tests and serum 5-hydroxytryptamine (5-HT) were assessed after methylglyoxal exposure. Our data showed that fecal water content was significantly higher than controls after methylglyoxal exposure except that of 30 mM group. Threshold volumes on balloon distension decreased in the treatment groups. All exposed rats showed obvious head scratching and grooming behavior and a decrease in sucrose preference. The serum 5-HT values were increased in 30, 60, 90 mM groups and decreased in 150 mM group. Our findings suggested that methylglyoxal could induce diarrhea, visceral hypersensitivity, headache as well as depression-like behaviors in rats, and might be the key role in triggering systemic symptoms of IBS.</p></div

Effects of methylglyoxal on sucrose preference test.

<p>The SPT scores of the 150 mM group were decreased. *<i>p</i><0.05 versus controls.</p

Effects of methylglyoxal on head scratching and grooming behaviors.

<p>The time of scratching behavior in all treatment groups markedly increased compared with controls. **<i>p</i><0.01 versus controls.</p

Effects of methylglyoxal on serum 5-HT level.

<p>The serum 5-HT levels of 30 mM, 60 mM and 90 mM groups were markedly higher than controls. The difference between 120 mM group and controls was not significantly. The level of 5-HT in 150 mM group rats was decreased than controls. **<i>p</i><0.01 versus controls, *<i>p</i><0.05 versus controls.</p