Bifunctional 3-Hydroxy-4-Pyridinones as Potential Selective Iron(III) Chelators: Solution Studies and Comparison with Other Metals of Biological and Environmental Relevance

The binding ability of five bifunctional 3-hydroxy-4-pyridinones towards Cu2+ and Fe3+ was studied by means of potentiometric and UV–Vis spectrophotometric measurements carried out at I = 0.15 mol L−1 in NaCl(aq),T = 298.15 K and 310.15 K. The data treatments allowed us to determine speciation schemes featured by metal-ligand species with different stoichiometry and stability, owing to the various functional groups present in the 3-hydroxy-4-pyridinones structures, which could potentially participate in the metal complexation, and in the Cu2+ and Fe3+ behaviour in aqueous solution. Furthermore, the sequestering ability and metal chelating affinity of the ligands were investigated by the determination of pL0.5 and pM parameters at different pH conditions. Finally, a comparison between the Cu2+ and Fe3+/3-hydroxy-4-pyridinones data herein presented with those already reported in the literature on the interaction of Zn2+ and Al3+ with the same ligands showed that, from the thermodynamic point of view, the 3-hydroxy-4-pyridinones are particularly selective towards Fe3+ and could therefore be considered promising iron-chelating agents, also avoiding the possibility of competition, and eventually the depletion, of essential metal cations of biological and environmental relevance, such as Cu2+ and Zn2+.

Utilization of agro-industrial by-products as substrates for dextransucrase production by leuconostoc mesenteroides T3: Process optimization using response surface methodology

Dextransucrase (DS) is a glucosyltransferase (E. C. 2.4.1.5) that catalyzes the transfer of glucosyl residues from sucrose to dextran polymer and liberates fructose. This enzyme is associated with a wide application range of dextran and oligosaccharides. DS production by Leuconostoc mesenteroides T3 was optimized using a Central Composite Design under the Response Surface Methodology. Three variables were chosen for optimization: distillery stillage, sucrose and manganese concentration. The results showed that sucrose and manganese concentrations had a positive linear effect on DS production while all variable interactions (stillage-manganese, stillage-sucrose, and sucrose-manganese) had significant influences on the DS production. The maximal DS yield of 3.391?0.131 U cm-3, was obtained in the medium with 64.33 % distillery stillage concentration, 5.30 % sucrose concentration and 0.022 % manganese concentration. Our study revealed the potential of distillery stillage combined with sugar beet molasses, supplemented with sucrose and manganese to be employed as a valuable medium growth for lactic acid bacteria and production of DS. Also, taking into consideration the origin of the substrates, utilization of industrial by-products in this way has a great environmental relevance and is in accordance with circular economy.

Sampling, handling, and preparation of peat cores from bogs: review of recent progress and perspectives for trace element research

Peat bogs are valuable archives of environmental change, including climate history, landscape evolution, and atmospheric deposition of trace elements, fallout radionuclides, and organic contaminants. Maintaining the fidelity of peat samples during collection and handling can be challenging, given that bogs consist mainly of fossil plant materials that typically have a very low density and are easily compressed. The surface layers of bogs, which are dominated by living plants and poorly decomposed fibrous peats, are especially problematic. To extract peat monoliths, we use a Belarus corer for deep layers and a Wardenaar device for surface layers. Both corers are constructed using titanium alloys to improve strength, reduce weight, and minimize the risk of contamination by the trace metals of environmental relevance. In this review, we include detailed drawings of the Belarus corer and photographs of the modifications to the Wardenaar corer. Modifications to the motorized Noernberg corer for frozen peat are described, and a complete set of drawings provided. A summary is given of simple procedures to minimize the risk of metal contamination in the laboratory from slicing and subsampling the peat cores and milling the dried samples.

Stand und Entwicklung des Fachplanungsrechts im Spiegel der jüngeren höchstrichterlichen Rechtsprechung

The report surveys in two parts the development of the law on project-related planning and thus relates in particular to the planning and approval of space-consuming infrastructure projects such as traffic routes and power lines. For this purpose, German administrative law has long provided for the specific instrument of plan approval (Planfeststellung). In this context, the Federal Administrative Court has extensive first-instance jurisdiction and uses this to shape large parts of German approval law, including beyond the actual area of plan approval law, be it in terms of legal protection and procedure, be it with regard to the requirements of substantive environmental law. On the other hand, the revision of the law on environmental protection induced by the decisions of the Aarhus Compliance Committee and the European Court of Justice has been used by the German legislator to extend procedural specifics of the plan approval to other approval decisions of environmental relevance. This firstly indicates the contours of a general law on project approval and, secondly, the nature of the plan approval as an instrument for the implementation of projects in the public interest is more strongly emphasized.