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C3–6 diols can be isolated from ethylene glycol (EG) via acid-catalyzed dehydration reactions, but the cost of catalyst and undesirable EG conversion have been concerns. Sulfonated silica gel with mesopores (5–12 nm) was prepared by impregnation and oxidation at a low cost, and it was more active than commercial Hβ zeolite in the catalytic transformation of C3–6 diols. The heat resistance of this material was much higher than Nafion and Amberlyst resins. With the adding of water, the undesirable acetalization reaction of EG was inhibited. The tuning effect of water on the conversions of diols was studied from the perspective of chemical equilibrium. XPS confirmed the existence of SO3H and a small quantity of SO2H groups on the catalyst, and the latter are responsible for the formation of undesirable acetals. This catalyst could be reused thrice with high conversions of C4–6 diols. Glycerol and other non-diol components weakened the reusability of catalyst. After reuse, the deposition of coke and leaching of acidic groups were verified by titration, NH3-TPD, and elemental analysis results. The catalyst could be incompletely regenerated via the removal of coke with H2O2. The solute in leachate was determined by 1H NMR and FTIR, and the cleavage of Si–C bond occurred during the leaching process. This leaching phenomenon was negligible at ≤ 90 °C. This cheap, strong Brønsted solid acid may find its applications in the catalysis field. [ABSTRACT FROM AUTHOR]

• The concept of open reactor, which integrates reaction with separation, was proposed. • Lactide was synthesized with a yield of 21.3 % via simple procedures under mild conditions. • The shift of chemical equilibrium was achieved by removing the reaction product. • Relative volatility and lactide yield were increased by adding γ -valerolactone. Lactide is an important building block of biodegradable polylactic acid. Lactide was synthesized via separation-promoted liquid-phase transesterification reactions of lactates. Amberlyst-15 resin exhibited relatively high catalytic activity due to its large number of strong Brønsted acid sites. Methyl lactate was much more reactive than butyl lactate due to its methyl group with smaller steric hindrance. The reactions were promoted by evaporating alcohol products with an open cylinder reactor with an opening degree of 5 %. In addition, the evaporation of substrate could be inhibited by adding a small quantity of γ -valerolactone. The lactide selectivity and yield reached 45.3 % and 18.2 %, respectively. After the recovery of starting materials for additional reaction, the overall yield of lactide reached 21.3 % (state-of-the-art: 45 %). The reaction pathway was clarified: Two methyl lactate molecules combined into an acyclic C 7 molecule via self-transesterification, followed by ring-closure reaction of this molecule. The SO 3 H groups on the resin catalyst were leachable, and coke was deposited on the catalyst, resulting in decrease of catalytic activity in reuse experiment. This direct synthesis method of lactide is much simpler than the conventional lactic-acid-based route, and the reaction conditions were much milder compared to other direct synthesis approaches. [Display omitted] [ABSTRACT FROM AUTHOR]

BACKGROUND The application of Pickering emulsions stabilized by food‐derived particles is of great interest, studies have focused on development of natural functional emulsifiers from agricultural byproducts. Dietary fiber (DF) has been recognizing for its excellent physiological functions. Moreover, physicochemical properties of pomelo peel DF (PDF) make it a potential emulsifier. However, pristine PDF is not suitable as emulsifier due to its compact physical structure and high hydrophobicity, which seriously limits its utilization. The objective of the study was to investigate the effects of cellulase on physicochemical properties of PDF and to illustrate the feasibility of cellulase modified PDF (MPDF) as natural functional emulsifier. RESULTS: Cellulase modification significantly improved (P < 0.05) specific surface area, water‐holding capacity/oil‐holding capacity, viscoelasticity, hydrophobicity, and pore structure while decreased crystallinity index and particle size of PDF. Emulsion could remain stable over 30 days as MPDF concentrations up to 1 wt% and oil/water ratio 3:7. The appearance stability of emulsions was not influenced by temperature (4–60 °C), pH (3.0–12.0), and ion concentration (0–200 mmol L−1) which was similar to Pickering emulsions. The mechanism of MPDF as an emulsifier was mainly attributed to the combination of Pickering effect and the three‐dimensional network. In addition, MPDF showed higher antioxidant capacity in emulsions than other classical emulsifiers. CONCLUSION: The results illustrated that MPDF has a favorable feasibility for preparation of stable Pickering‐type emulsions, which will be a practical support for application of PDF as a natural functional emulsifier and will be helpful to realize the resource utilization of DF in pomelo industries. © 2022 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

[Display omitted] • Pomelo peel insoluble dietary fiber (PIDF) can be used as an effective emulsifier; • Micronization by ball milling cannot fully support emulsifying capacity of PIDF; • Cellulase endowed PIDF emulsibility combined Pickering and 3D network mechanism; • Further ball milling after cellulase made PIDF lose emulsification gradually; • Breakage of intact porous structure of PIDF cause reduced emulsion stability. Emulsion gels from the pomelo peel insoluble dietary fiber (PIDF) were developed. The emulsification potentials of PIDFs subjected to various degrees of ball milling (M−PIDFs), cellulase hydrolysis (C-PIDF), and cellulase hydrolysis followed by ball milling (CM-PIDFs) were evaluated. Emulsions prepared by M−PIDFs for different lengths of ball milling time exhibited similar stability characteristics, confirming that M−PIDF emulsion stability might be determined by the three-dimensional structure formed by M−PIDF stacking and oil droplet capture. C-PIDF had characteristics resembling those of Pickering particles. CM-PIDF emulsions got destabilized with ball milling time prolongation. Interface tension and particle size of C/CM-PIDF decreased gradually during ball milling. Rheological and fluorescence microscopy results revealed that the intact internal crosslinking structure frameworks were disrupted in CM-PIDF emulsions. Therefore, intact fiber-based networks, rather than small particle size or low interfacial tension, determine the stability of PIDF emulsions. This study deepens the understanding of PIDF as a clean emulsifier. [ABSTRACT FROM AUTHOR]

Insoluble fibers are not commonly used as emulsion stabilizers because of their compact physical structure and strong hydrophilicity. In this study, pomelo insoluble fibers (PISFs) prepared via cellulase hydrolysis and cellulase hydrolysis followed by octenyl succinic anhydride esterification were used as emulsifiers. The fabricated fibers are denoted as MPISF and OMPISFs, respectively. Unlike MPISF, the OMPISFs with different degrees of substitution (i.e., OMPISF(I) and (II)) increased in the ζ-potentials and contact angles but decreased in the oil-water interfacial tensions to different degrees. Furthermore, an 0.5 wt% OMPISF(II) content was required to prepare a stable non-creaming emulsion, whereas the corresponding MPISF and OMPISF(I) contents were 0.75 wt%. The OMPISF(II)-stabilized emulsions did not undergo creaming after three freeze-thaw treatment cycles. Therefore, the properties of the OMPISF(II)-stabilized emulsions were superior to those of the MPISF- and OMPISF(I)-stabilized emulsions. Additionally, the final amount of free fatty acids released by the OMPISF(II)-stabilized emulsion was 13.3% lower than that released by the MPISF-stabilized emulsion during simulated gastrointestinal digestion. During lipid oxidation processes, the amounts of lipid hydroperoxide and thiobarbituric acid reactive substance produced in the OMPISF(II)-stabilized emulsion were 41.3% and 40.0% lower, respectively, than those in the MPISF-stabilized emulsion. OMPISFs improved the emulsion properties by increasing the oil–water interface stability, forming more solid three-dimensional structures, and promoting electrostatic repulsion between emulsion droplets. These findings indicate that pomelo peel dietary fiber is a promising emulsifier with excellent application potential for the preparation of emulsion stabilizers. [Display omitted] • Dual modification of OSA and cellulase endowed PISF an excellent emulsibility. • Freeze-thaw, digestion and oxidative stability of emulsions were improved by OSA. • Higher DS provide emulsions with higher stabilization and application properties. • Improved network, interface layer and electrostatic value were the main mechanism. • This study facilitates the development of utilization of pomelo peel as emulsifier. [ABSTRACT FROM AUTHOR]

5‐Hydroxymethylfurfural (HMF) was transformed into 2,5‐diformylfuran (DFF) with nitric acid as the oxidant. The initial HMF content was as high as 12.5 wt %, and water was the sole solvent. This is an intensely exothermic reaction along with the emission of NO2 gas. A high DFF yield of 83.2 % was achieved if the oxidation ability of nitric acid matched with the requirement of target oxidation reaction while mismatched those of side reactions by regulating the initial concentration of nitric acid (59.5 wt %) and reaction temperature (50–60 °C). The oxidation reaction of HMF, overoxidation of HMF, and skeleton‐cracking reaction of FDCA preferred concentrated HNO3, hot HNO3, and concentrated or hot HNO3, respectively. After liquid‐liquid extraction, filtration, and column chromatography, light‐yellow DFF powders with purity of 92.1 wt % and isolated yield of 40.2 % were obtained and confirmed by NMR, FTIR, UV‐Vis, and elemental analysis. HMF was the dominant impurity due to its affinity to DFF. In addition, chromogenic substances were obtained as a byproduct, and they were potential pH indicators. These chromogenic substances had highly conjugated molecular structures, and they were generated via successive β‐protonation‐based ring‐opening reaction of HMF, aldol reaction, and dehydration reaction. [ABSTRACT FROM AUTHOR]

For the controllable transformation of C3–6 diols in ethylene glycol (EG), a H-Beta zeolite catalyst was modified with NH3via incomplete desorption. 60.8% of acid sites on the zeolite were deactivated, but the ratio of strong acid sites was obviously increased. With 1,2-pentanediol (PDO) as a representative large-carbon-number diol, the undesirable acetalization and oligomerization reactions of EG were suppressed in the EG-PDO reaction system over the modified catalyst due to their dependency on total acid sites. NH3-TPD and FTIR results proved that Lewis acid sites on the modified zeolite were eliminated after modification, resulting in the suppression of acetalization and oligomerization reactions. In contrast, a portion of strong Brønsted acid sites still remained, ensuring the catalytic transformation of PDO. Only 8.2% of EG was consumed after 8 h reaction, and the conversion of PDO could reach 84.3%. The loading of NH3 on the surface of zeolite pores led to diffusion resistance, slightly decreasing the reaction rate of PDO without affecting the reaction selectivity. The catalytic reactions of other C3–6 diols in EG followed similar principles, and the selectivity to aldehydes or ketone was improved over this modified catalyst. Non-diol biomass hydrogenation products such as glycerol had a negative influence on the selectivity, so these components should be isolated before the reactions. This catalyst could be reused at least 5 times, and the conversion of PDO slightly decreased. This work sheds light on the relationships between the acid properties of the catalyst and different reactions of diols. [ABSTRACT FROM AUTHOR]

Phosphate (Pi) availability has become a major constraint limiting crop growth and production. Heat shock factors (Hsfs) play important roles in mediating plant resistance to various environmental stresses, including heat, drought and salinity. However, whether members of the Hsf family are involved in the transcriptional regulation of plant responses to Pi insufficiency has not been reported. Here, we identified that TaHsfA2d , a member of the heat shock factor family, was strongly repressed by Pi deficiency. Overexpressing TaHsfA2d-4A in Arabidopsis results in significantly enhanced sensitivity to Pi deficiency, evidenced by increased anthocyanin content, decreased proliferation and elongation of lateral roots, and reduced Pi uptake. Furthermore, RNA-seq analyses showed that TaHsfA2d-4A functions through up-regulation of a number of genes involved in stress responses and flavonoid biosynthesis. Collectively, these results provide evidence that TaHsfA2d participates in the regulation of Pi deficiency stress, and that TaHsfA2d could serve as a valuable gene for genetic modification of crop tolerance to Pi starvation. • Heat shock factor (Hsf) genes are reported to be involved in plant responses to phosphate deficiency for the first time. • The expression of wheat TaHsfA2d was repressed by phosphate deficiency. • Overexpression of the TaHsfA2d-4A gene in Arabidopsis results in significantly enhanced sensitivity to phosphate deficiency. • TaHsfA2d-4A functions through regulating the expression of flavonoid biosynthesis and stress-related genes. [ABSTRACT FROM AUTHOR]

TMSCFX2 (X = Cl, Br; TMS = trimethylsilyl) have been developed as halofluorocarbene (CFX, X = Cl, Br) precursors for [2+1] cyclopropanation with alkenes. Structurally diverse halofluorocyclopropanes were obtained in good to excellent yields. It was found that the reactivity order of the three halofluorocarbene reagents (TMSCF2Br, TMSCFCl2, and TMSCFBr2) in halofluorocyclopropanation with 1,1-diphenylethylene can be very different under different reaction conditions. [ABSTRACT FROM AUTHOR]

Acid-soluble (ASC) and pepsin-soluble (PSC) collagens were isolated from tilapia skin and were characterized as type I collagen. The T d (denaturation temperature) of ASC and PSC was 26.80 and 28.20 °C, respectively. CD (circular dichroism) and FTIR (Fourier transform infrared) spectra of ASC and PSC were slightly different, which confirmed that limited digestion by pepsin disrupted the triple helical structure of collagen. The microstructure depicted a homogeneous, compact, fibrillary, and multilayered sheet-like structure. Notably, no toxicologically effect (survival rate, behavioral activity, respiratory illness, abdominal irritation, eye lid and prolapse) was observed in collagen treated mice. The body weight of the ASC-treated mice (36.1–38.6 g) was significantly higher than that of the PSC-treated mice (32.9–36.7 g). In vitro absorption properties revealed that type I collagen hydrolysates with molecular weights (MWs) ranging from 100 to 12 kDa were effectively absorbed by intestinal villi. Taken together, these results suggest that tilapia type I collagen at the concentrations of 25 and 50 mg/kg bw has no higher risk of chronic toxic effects in mice. Therefore, it was concluded that the administration of tilapia type I collagen had low toxicity and confirmed the in vivo biocompatibility for its wide application in the biomedical industries. [ABSTRACT FROM AUTHOR]

Abstract: Protoporphyrin IX (PpIX) has been used as a sensitizer in photodynamic therapy (PDT) as well as in sonodynamic therapy (SDT). The photo-bleaching of PpIX has been well investigated in many experimental systems and some photo-products have also been identified in PDT. But until now, little information has been reported about the sono-damage of PpIX in SDT. So, the present study was to investigate changes of PpIX properties before and after different ultrasound treatment, and the potential interactions between PpIX, ultrasound and the irradiated cells. In cell-free system, the absorption and fluorescence spectra of PpIX in different solutions were measured by ultraviolet spectrometer and fluorescence spectrophotometer, respectively. The terephthalic acid dosimetry was applied to evaluate the efficiency of ultrasound cavitation by monitoring hydroxyl radical ( OH) production on the thermolysis of H2O in the ultrasound field. In in vitro study, confocal microscopy was applied to detect the sub-cellular localization of PpIX in S180 cells before and after ultrasound exposure. Flow cytometry was used to detect the reactive oxygen species (ROS) generation during PpIX–SDT. MTT assay was performed to evaluate the cell viability of S180 cells after SDT treatment with or without ROS scavengers. The results show that PpIX displayed different spectral patterns in different solutions. PpIX was decomposed by ultrasound exposure as measured by the decreased absorption and fluorescence peak values in RPMI-1640 medium. In addition, the decomposition of PpIX was found to be simultaneously accompanied by OH production with increasing output power from ultrasound generator. PpIX at 1μg/ml significantly enhanced the ultrasound induced cavitation as measured by OH generation, and which was greatly eliminated by NaN3, histidine, mannitol, EDTA and catalase, but not by SOD. The in vitro study indicates more PpIX entered into S180 cells after ultrasound exposure. And, the extra-cellular PpIX play an important role in the enhanced cell killing of PpIX–SDT. SDT induced obvious ROS generation in S180 cells, which could be mostly inhibited by the general ROS scavenge NAC (N-acetylcysteine). Other scavengers such as NaN3, histidine, mannitol all partially prevented the SDT induced cell viability loss of S180 cells, suggesting OH, 1O2 might be involved during the process. [Copyright &y& Elsevier]

• Broken rice hydrolysate was used as carbon source. • The pH decreased sharply leading to failure of microalgal growth. • Ammonium led to a decrease in the pH of the medium. • Batch pH adjustment could increase biomass production of Chlorella vulgaris. • The cost of the culture medium decreased by 89.58%. The high cost of carbon source limits the heterotrophic culture of Chlorella. In this study, broken rice was hydrolyzed into glucose. Then, the broken rice hydrolysate (BRH) was utilized for heterotrophic cultivation of C. vulgaris instead of glucose. Results showed that algal cells released H+ when they consumed NH 4 +, leading to a sharp decrease in pH. Growth inhibition by acid could be avoided by using a pH buffer. Adding alkaline reagents intermittently during culture could not only reduce the amount of pH stabilizer but also obtain increased biomass production. When using Tris as pH stabilizer, the biomass productivity of C. vulgaris in BRH was the largest (1.01 g/L/d), followed by NaOH (1.00 g/L/d), and Na 2 CO 3 (0.95 g/L/d). Using BRH instead of glucose for heterotrophic cultivation of C. vulgaris could save 89.58% of the cost of culture medium. This study developed a novel strategy for cultivating C. vulgaris heterotrophically using BRH. [ABSTRACT FROM AUTHOR]