Production of a novel pyranose 2-0xidase by basidiomyceteTrametes multicolor

During a screening for the enzyme pyranose 2-oxidase (P2O) which has a great potential as a biocatalyst for carbohydrate transformations, Trametes multicolor was identified as a promising, not-yet-described producer of this particular enzyme activity. Furthermore, it was found in this screening that the enzyme frequently occurs in basidiomycetes. Intracellular P2O was produced in a growth-associated manner by T. multicolor during growth on various substrates, including mono-, oligo-, and polysaccharides. Highest levels of this enzyme activity were formed when lactose or whey were used as substrates. Peptones from casein and other casein hydrolysates were found to be the most favorable nitrogen sources for the formation of P2O. By applying an appropriate feeding strategy for the substrate lactose, which ensured an elevated concentration of the carbon source during the entire cultivation, levels of P2O activity obtained in laboratory fermentations, as well as the productivity of these bioprocess experiments, could be enhanced more than 2.5-fold.     

Application of adsorptive stripping voltammetry (AdSV) for the analysis of trace metals in brine

Summary Routine analysis of brine for trace metals is important for safe and economical production in the alkali chloride electrolysis. As opposed to many spectroscopic techniques, trace metal determination by adsorptive stripping voltammetry (AdSV) is shown to be performed directly in brine. With minimal sample preparation chromium(VI), iron(III), nickel(II), cobalt(II), titanum(IV), manganese(II), molybdenum(VI) and vanadium(V) can be determined within minutes. The influence of parameters such as pH-value, supporting electrolyte solution, concentration of complexing reagents and possible interferents are investigated for optimal experimental conditions. Minimum detection limits are less than 5 ng/g for all trace metals except 1 ng/g for chromium(VI), cobalt(II) and molybdenium(VI) for 40 s adsorption periods with precisions of better than 7%. AdSV with linear or differential pulse scan is discussed.     

Activation of Elemental Sulfur at a Two‐Coordinate Platinum(0) Center

Platinum dichalcogenides have been known to exhibit two‐dimensional layered structures. Herein, we describe the syntheses, isolation, and characterization of air‐stable crystalline cyclic alkyl(amino) carbene (cAAC)‐supported monomeric platinum disulfide three‐membered ring complex [(cAAC)₂Pt(S₂)] ( 2 ). The highly reactive platinum(0) [(cAAC)₂Pt] complex ( 1 ) with two‐coordinate platinum activates elemental sulfur to give 2 . The brown crystals of bis‐carbene platinum(II)monosulfate [(cAAC)₂Pt(SO₄)_x(S₂)_1?x] ( 4 ) have been isolated when the reaction was performed in air. The dioxygen analogue of 2 was formed upon exposing the THF solution of 1 to aerial oxygen (O₂). The binding of oxygen at the Pt⁰ center was found to be reversible. Additionally, DFT study has been performed to elucidate the electronic structure and bonding scenario of 2 , 3 , and 4 . Quantum chemical calculations showed donor–acceptor‐type interaction for the Pt?S bonds in 2 and Pt?O bonds in 3 and 4 .     

Solid-State NMR-Driven Crystal Structure Prediction of Molecular Crystals: The Case of Mebendazole

Among all possible NMR crystallography approaches for crystal-structure determination, crystal structure prediction – NMR crystallography (CSP-NMRX) has recently turned out to be a powerful method. In the latter, the original procedure exploited solid-state NMR (SSNMR) information during the final steps of the prediction. In particular, it used the comparison of computed and experimental chemical shifts for the selection of the correct crystal packing. Still, the prediction procedure, generally carried out with DFT methods, may require important computational resources and be quite time-consuming, especially if there are no available constraints to use at the initial stage. Herein, the successful application of this combined prediction method, which exploits NMR information also in the input step to reduce the search space of the predictive algorithm, is presented. Herein, this method was applied on mebendazole, which is characterized by desmotropism. The use of SSNMR data as constraints for the selection of the right tautomer and the determination of the number of independent molecules in the unit cell led to a considerably faster process, reducing the number of calculations to be performed. In this way, the crystal packing was successfully predicted for the three known phases of mebendazole. To evaluate the quality of the predicted structures, these were compared to the experimental ones. The crystal structure of phase B of mebendazole, in particular, was determined de novo by powder diffraction and is presented for the first time in this paper.     

Significance of epoxy network properties for the toughening effect of flaky and fullerene‐like WS2 nanoparticles

This work deals with the toughening effect of flaky WS₂ and fullerene‐like WS₂ (IF‐WS₂) nanoparticles on epoxy with varying network properties. Reducing the amount of curing agent resulted in decreased crosslink density as measured by dynamic‐mechanic analysis and double‐quantum nuclear magnetic resonance spectroscopy. Although that lead to moderate changes in the epoxy's tensile properties, its fracture toughness dropped drastically, probably due to an increased defect fraction. IF‐WS₂ could be dispersed significantly more effectively within epoxy resin than flaky WS₂, possibly due to its spherical shape, but caused less toughening. IF‐WS₂ tended to debond from the epoxy, while flaky WS₂ introduced more secondary cracks. Both increased the fracture toughness of the (brittle) substoichiometric, but not that of the (tough) stoichiometric epoxy, possibly due to their interaction with molecular defects. Irrespective of which mechanism resulted in the toughening effect, its effectiveness depended strongly on the epoxy matrix. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1738–1747