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Hydrogen (H2) is recognized as a clean energy carrier with great potential for the future energy systems. Given the existing challenges in direct H2 storage and delivery, the current option for utilizing hydrogen energy is to produce hydrogen from its storage carriers on‐site, and the development of a highly active, highly selective, and highly stable catalyst for H2 production is an important part of this. Herein, PdAg alloy was deposited on mesoporous carbon nitride (mpg‐C3N4) as a catalyst for the dehydrogenation of the formic acid (FA). The synergistic effect of Pd and Ag metals for catalysis was explored. The role of the supports on the catalytic performance was also demonstrated by depositing PdAg alloy on several carriers of Silica@Resorcinol‐Formaldehyde Spheres, Carbon Flower Particles and SBA‐15. Pd1Ag1/2/mpg‐C3N4 showed a considerable activity during FA dehydrogenation with a turnover frequency (TOF) value of 887 h−1 at 333 K, demonstrating that carbon nitride as a carrier has a significant enhancement on the catalytic hydrogen production from formic acid. [ABSTRACT FROM AUTHOR]

As a result of the poor mechanical properties of most metal–organic frameworks (MOFs), they are liable to dissociate in water and thus cannot maintain immobilized enzyme activity. In this paper, a magnetic porous carbon material (Fe‐Cu‐MPC) with good stability was prepared by high temperature carbonization using a bimetallic Fe‐Cu‐MOF precursor, and used to immobilize laccase by a simple and rapid adsorption‐crosslinking method. Optimized by the response surface method, optimal conditions for the immobilization of laccase on Fe‐Cu‐MPC were obtained as follows: enzyme concentration 1.275 mg mL−1, immobilization time 32 min, and pH 4.7. Under the optimal preparation conditions, the activity of the immobilized laccase obtained was 0.63 U mg−1, with activity recovery of 63.13%. The enzyme loading was 189.03 mg g−1 and the immobilization yield was 74.13%. Compared with free laccase, Fe‐Cu‐MPC@Lac showed stronger tolerance to temperature and pH, and had better thermal stability and storage stability. The removal of BPA by immobilized laccase was studied, showing that the removal effect of Fe‐Cu‐MPC@Lac on BPA was much higher than that of free laccase. Within 5 h, the BPA removal amount of Fe‐Cu‐MPC@Lac (0.34 mmol g−1) was two‐fold that of free laccase (0.14 mmol g−1), and the BPA removal rate reached 41.35% after ten cycles. Finally, based on the intermediates identified by gas chromatography–mass spectrometry, two possible degradation pathways of BPA were proposed. Studies have shown that Fe‐Cu‐MPC is an excellent carrier and Fe‐Cu‐MPC@Lac has great potential in the treatment of BPA containing wastewater. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In this study, an amino-functionalized magnetic silica microsphere material (Fe3O4-SiO2-NH2) was prepared. Using glutaraldehyde as a cross-linking agent, Trametes versicolor laccase was adsorbed-covalently bonded and immobilized on the material to prepare Laccase @ Fe3O4-SiO2. In addition, the materials were characterized and analysed by SEM, TEM, XRD, FT-IR and VSM. Finally, the thermal inactivation dynamics of immobilized laccase in polar/non-polar/toxic systems and the adsorption and degradation of 2,4-DCP were studied. The results showed that Laccase @ Fe3O4-SiO2 under the optimal conditions (pH 6, temperature 65°C, initial concentration of 2,4-DCP 10 mg/L), the removal rate was as high as 81.6%. Moreover, compared with free laccase, immobilized laccase had good tolerance under low pH and high-temperature conditions, and storage stability was also greatly improved. After repeated use for 7 times, Laccase @ Fe3O4-SiO2 can still maintain 59% removal rate of 2,4-DCP, which gives it the potential for industrial applications. [ABSTRACT FROM AUTHOR]

The degradation of persistent organic pollutants (POPs) in the simulated wastewaters was investigated by Fe-C micro-electrolysis system. With phenanthrene (PHE) and 2,4-dichlorophenol (2,4-DCP) as target pollutants, different iron-carbon (Fe-C) micro-electrolysis systems have been established. The effects of initial pH, Fe/C mass ratio, and intake air flow on the degradation and mineralization of PHE and 2,4-DCP were studied. At the initial pH of 5.0, Fe/C of 1.5:1, and an aeration flow rate of 1.5 L/min, after 120 min of reaction, the removal efficiency of FHE and COD was 94.3% and 73%, respectively. Under the conditions of initial pH is 3.0, Fe/C is 1:2, aeration flow rate of 1.5 L/min, and reaction time of 90 min, the best removal efficiency of 2,4-DCP can be obtained in the Fe-C micro-electrolysis system as 97% and COD removal efficiency can reach 76%. The results of kinetic studies show that the Fe-C micro-electrolysis process of PHE and 2,4-DCP follows pseudo-first-order kinetics. Commercial activated carbon (AC) was used for comparison under the same condition. The results indicated that the removal rate of organic pollutants and chemical oxygen demand (COD) of Fe-C micro-electrolysis were superior to that of AC. Analyze the structure of iron after reaction by SEM and XRD. The degradation pathway and mechanism for PHE and 2,4-DCP were proposed based on LC-MS analyses of treated wastewater. [ABSTRACT FROM AUTHOR]

In this study, rice straw was used as the raw materials of biomass carbon to prepare biochar at different temperatures (400°C, 500°C, 600°C, 700°C, and 800°C). In addition, cetyl trimethyl ammonium bromide (CTAB) modified biochar was used to treat 2,4-dichlorophenol (2,4-DCP) in water. The influences of adsorbent dosage, solution pH, adsorption time, and initial solubility of the 2,4-DCP solution on the adsorption properties were investigated. The physicochemical properties of biochar were investigated using SEM, FT-IR, BET surface area, and pore size analysis. The results showed that the pyrolysis temperature had a great influence on the biochar structure. CTAB provided hydrophilic and hydrophobic groups to the modified biochar, which had increased adsorption capacity comparing to unmodified biochar. The pH also had a significant effect on the adsorption performance of biochar, and the adsorption performance of biochar decreased significantly under alkaline conditions. The maximum adsorption capacities of modified biochar and unmodified biochar were 59.81 and 20.89 mg/g, respectively, indicating that the adsorption capacity of modified biochar was significantly higher than that of unmodified biochar. The adsorption process of 2,4-DCP by rice straw biochar conformed to the Second-order kinetic model and the Freundlich isotherm adsorption model. [ABSTRACT FROM AUTHOR]

In this paper, ultrasound was used to enhance the degradation effect of laccase for 2,4-dichlorophenol (2,4-DCP) in soil. The degradation effect and mechanism of the ultrasound-enhanced laccase were investigated. From the results, the degradation rate of 2,4-DCP can reach as high as 51.7% under the following conditions: reaction period was 21 h, pH = 5.5, ultrasound power was 240 W, duty cycle was 50%, and moisture content was 50%. Using the ultrasound-enhanced laccase, the degradation rate of 2,4-DCP was significantly higher than that using only laccase or only ultrasound. In addition, when ultrasound was used, the optimum pH for the degradation of 2,4-DCP using laccase was increased, making the degradation technology more practical. The analysis results from high-performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC–MS) revealed the degradation pathway of 2,4-DCP in soil: first, 2,4-DCP gradually became phenol through dechlorination, then the small molecular organic matter was generated from the hydroxyl radical or laccase reaction. [ABSTRACT FROM AUTHOR]

In this paper, laccase is immobilized by the cross-linking method, using organic fertilizer as a carrier and glutaraldehyde as a cross-linking agent. Here, the optimal conditions of laccase immobilization were explored and the optimal operating conditions and stabilities of free laccase and immobilized laccase were also studied. Then, free laccase and immobilized laccase were applied to the soil remediation. Meanwhile, the effect of soil improvement treated with immobilized laccase was studied through ecological evaluation. The results showed that the optimal conditions for laccase immobilization were: the volume fraction of glutaraldehyde was 5%, the amount of enzyme added was 15 mL, and the immobilization time was 6 h. Under the same conditions, thermal stability and acid-base stability of immobilized laccase were better than free laccase. Under the optimal conditions, using laccase to treat 2,4-dichlorophenol in the soil, it was found that the free laccase group degraded 44.4% within 5 days, while the immobilized laccase group degraded 58.6%. Although both the degradation trends and route are the same, the degradation effect of the latter is obviously better. Ecological evaluation showed that organic fertilizer carrier had an impact on soil physical and chemical properties and soil enzymes, playing a positive role in soil ecological security and improving the soil. [ABSTRACT FROM AUTHOR]

The collision-induced dissociation (CID) of the copper-cytidine complex [CuL] (L is cytidine, n = 2-4) shows that the inter-ligand proton transfer (PT) is the dominating process. This is quite different from the CID of copper-guanosine complex [CuG] (G is guanosine, n = 2-4), in which the inter-electron transfer (ET) dominates. The possible structures and zero-point energies for the majority of these structures were calculated using density functional theory (DFT) methods, and the Δ G Gibbs energy analysis of the CID processes also demonstrated the difference between the two complex structures. The results show that the steric hindrance effects and the intermolecular hydrogen bonds are the main reasons that cause the coordination between Cu(II) and the ligands of the cytidine and guanosine molecule. Cu(II) coordinates 4 ligands for [CuL], forming the primary order sphere and presenting non-covalent bonding of the ligands. A greater steric effect was observed in the purine ring, which could be unstable if the guanosine molecules distributed around the copper ions to form coordination compounds. The [CuG] complex tends to form intermolecular hydrogen bonds to enhance its structural stability by amino N and carbonyl O of purine ring. [ABSTRACT FROM AUTHOR]

In this study, an amino-functionalized magnetic silica microsphere material (Fe 3 O 4 -SiO 2 -NH 2 ) was prepared. Using glutaraldehyde as a cross-linking agent, Trametes versicolor laccase was adsorbed-covalently bonded and immobilized on the material to prepare Laccase @ Fe 3 O 4 -SiO 2 . In addition, the materials were characterized and analysed by SEM, TEM, XRD, FT-IR and VSM. Finally, the thermal inactivation dynamics of immobilized laccase in polar/non-polar/toxic systems and the adsorption and degradation of 2,4-DCP were studied. The results showed that Laccase @ Fe 3 O 4 -SiO 2 under the optimal conditions (pH 6, temperature 65°C, initial concentration of 2,4-DCP 10 mg/L), the removal rate was as high as 81.6%. Moreover, compared with free laccase, immobilized laccase had good tolerance under low pH and high-temperature conditions, and storage stability was also greatly improved. After repeated use for 7 times, Laccase @ Fe 3 O 4 -SiO 2 can still maintain 59% removal rate of 2,4-DCP, which gives it the potential for industrial applications.

Oceans have remained the least well-researched reservoirs of persistent organic pollutants (POPs) globally, due to their vast scale, difficulty of access, and challenging (trace) analysis. Little data on POPs exists along South America and the effect of different currents and river plumes on aqueous concentrations. Research cruise KN210-04 ( R/V Knorr ) offered a unique opportunity to determine POP gradients in air, water, and their air-water exchange along South America, covering both hemispheres. Compounds of interest included polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenylethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs). Remote tropical Atlantic Ocean atmospheric concentrations varied little between both hemispheres; for HCB, BDEs 47 and 99, they were ∼5 pg/m 3 , PCBs were ∼1 pg/m 3 , α-HCH was ∼0.2 pg/m 3 , and phenanthrene and other PAHs were in the low 100s pg/m 3 . Aqueous concentrations were dominated by PCB 52 (mean 4.1 pg/L), HCB (1.6 pg/L), and β-HCH (1.9 pg/L), with other compounds <1 pg/L. Target PCBs tended to undergo net volatilization from the surface ocean, while gradients indicated net deposition for a -HCH. In contrast to atmospheric concentrations, which were basically unchanged between hemispheres, we detected strong gradients in aqueous POPs, with mostly nondetects in the tropical western South Atlantic. These results highlight the importance of currents and loss processes on ocean scales for the distribution of POPs.

Objective: The aim of this study was to further increase the yield of insulin precursor by Pichia pastoris., Methods: For this, we transformed the expression vector pPICZalpha-IP into P. pastoris X-33 using electroporation and screened two mutant strains B4 and S6 on the YPD plate containing 100 microg/mL zeocin. Both could overexpress human insulin precursor. Taking B4 and S6 as start strains, we repeatedly transformed SacI linearizing pPICZalpha-IP into P. pastoris X-33 by electroporation, then screened a new mutant strain 2B4 (with 7 copies) on the 1000 microg/mL zeocin YPD plate., Results: After cultivation, the human insulin precursor yield of 2B4 strain was 2.7 fold higher than that of B7. Meanwhile, the cell growth was not inhibited. The target gene transcription level of 2B4 was 2 fold higher than that of B7 by real-time quantification PCR., Conclusion: The strategy of combining resistance screening and repeated electroporation was efficient to increase the copy number of target gene, so as to facilitate higher transcription level and enhance objective recombinant protein yield.