Spray congealing for immobilization of biocatalysts

Spray congealing was investigated as new innovative immobilization technique for biocatalysts. The immobilization is realized by an atomization of a suspension or emulsion of a melted carrier and the enzyme, which is re-solidifyed due to temperature decrease. This method needs neither organic solvents nor a difficult downstream processing after preparation. For the encapsulation different matrices, like long chain alcohols and glyceryl derivatives, with melting points below 86 °C and environmentally friendly properties were chosen and tested for their suitability for enzyme encapsulation. Spray congealing is widely used for pharmaceutically active ingredients, but has not been described for enzymes so far [1]. The immobilization of a laccase, (Novozym 51003, from Myceliophthora thermophila), was investigated and the produced microparticles were characterized. The obtained particles showed a mean particle size around 40 µm and a spherical surface with different structures depending on the used matrix. Spray congealing with the laccase reached yields of 80 % and residual activities up to 56%. Furthermore 4 consecutive reactions with 20% retained activity of in cetyl alcohol immobilized enzyme were realized. Cetyl alcohol was found to be the most appropriate carrier for the immobilization of the investigated laccase, due to an easy handling and high yields. In addition, the best retained activities were obtained and a recycling of the biocatalyst could be realized [2]. Please click Additional Files below to see the full abstract

Una introducción a la traducción científica

Sección: Reseñas bibliográficas. Http://www.medtrad.orgEsta obra del traductor y profesor francés Jean Maillot (1905-1993) no es un tratado teórico de traducción ni un manual de metodología de la traducción, sino una exposición sencilla y clara de algunos de los problemas de la traducción científica y técnica a través de una abundante acumulación de casos concretos extraídos del francés, alemán, inglés y ruso.Peer reviewe

Oxidative Esterification of 5-Hydroxymethylfurfural under Flow Conditions Using a Bimetallic Co/Ru Catalyst

Furanic di-carboxylate derivatives of 5-Hydroxymethylfurfural (HMF) are nowadays important in the polymer industry as they are used as building blocks for bio-based polyesters. The high reactivity of HMF compels to avoid harsh synthetic conditions. Therefore, developing mild catalytic processes for its selective oxidation is a challenging task. Herein, we report the first oxidative esterification of HMF to dimethyl furan-2,5-dicarboxylate (FDCM) under flow conditions using oxygen as oxidant. For that purpose, a new series of nitrogen-doped carbon-supported bimetallic Co/Ru heterogeneous catalysts were prepared and characterized by XRD, XPS and N2 physisorption. These analyses revealed that the porosity of the materials and order of impregnation of the metals to the carbon supports lead to varying catalytic activities. Under optimized conditions the flow reactor showed a 15-fold increase on the production of FDCM compared to batch conditions. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA

Swelling and Mechanical Characterization of Polyelectrolyte Hydrogels as Potential Synthetic Cartilage Substitute Materials

Hydrogels have become an increasingly interesting topic in numerous fields of application. In addition to their use as immobilization matrixes in (bio)catalysis, they are widely used in the medical sector, e.g., in drug delivery systems, contact lenses, biosensors, electrodes, and tissue engineering. Cartilage tissue engineering hydrogels from natural origins, such as collagen, hyaluronic acid, and gelatin, are widely known for their good biocompatibility. However, they often lack stability, reproducibility, and mechanical strength. Synthetic hydrogels, on the other hand, can have the advantage of tunable swelling and mechanical properties, as well as good reproducibility and lower costs. In this study, we investigated the swelling and mechanical properties of synthetic polyelectrolyte hydrogels. The resulting characteristics such as swelling degree, stiffness, stress, as well as stress-relaxation and cyclic loading behavior, were compared to a commercially available biomaterial, the ChondroFiller® liquid, which is already used to treat articular cartilage lesions. Worth mentioning are the observed good reproducibility and high mechanical strength of the synthetic hydrogels. We managed to synthesize hydrogels with a wide range of compressive moduli from 2.5 ± 0.1 to 1708.7 ± 67.7 kPa, which addresses the span of human articular cartilage

Low-melting manganese(II)-based ionic liquids: syntheses, structures, properties and influence of trace impurities

The synthesis of more than 10 new magnetic ionic liquids with [MnX4]2 anions, X = Cl, NCS, NCO, is presented. Detailed structural information through single-crystal X-ray di raction is given for (DMDIm)[Mn(NCS)4], (BnEt3N)2[Mn(NCS)4], and {(Ph3P)2N}2[Mn(NCO4)] 0.6H2O, respectively. All compounds consist of discrete anions and cations with tetrahedrally coordinated Mn(II) atoms. They show paramagnetic behavior as expected for spin-only systems. Melting points are found for several systems below 100 C classifying them as ionic liquids. Thermal properties are investigated using di erential scanning calorimetry (DSC) measurements. The physicochemical properties of density, dynamic viscosity, electrolytic conductivity, and surface tension were measured temperature-dependent of selected samples. These properties are discussed in comparison to similar Co containing systems. An increasing amount of bromide impurity is found to a ect the surface tension only up to 3.3%

Coagulation using organic carbonates opens up a sustainable route towards regenerated cellulose films

Due to their biodegradability, biocompatibility and sustainable nature, regenerated cellulose (RC) films are of enormous relevance for green applications including medicinal, environmental and separation technologies. However, the processes used so far are very hazardous to the environment and health. Here, we disclose a simple, fast, environmentally friendly, nontoxic and cost-effective processing method for preparing RC films. High quality non-transparent and transparent RC films and powders can be produced by dissolution with tetrabutylphosphonium hydroxide [TBPH]/[TBP]+[OH]− followed by coagulation with organic carbonates. Investigations on the coagulation mechanism revealed an extremely fast reaction between the carbonates and the hydroxide ions. The high-quality powders and films were fully characterized with respect to structure, surface morphology, permeation and selectivity. This method represents a future-oriented green alternative to known industrial processes. © 2020, The Author(s)

BioOK – a Comprehensive System for Analysis and Risk Assessment of Genetically Modified Plants

Gentechnisch veränderte (GV) Pflanzen müssen im Rahmen des Zulassungsverfahrens in der EU auf ihre potentiellen Auswirkungen auf die Umwelt und die mensch­liche oder tierische Gesundheit analysiert werden. Der gegenwärtige Zulassungsprozess ist ein Konglo­merat verschiedenster Analysemethoden und extrem zeit- und kostenaufwendig. Das Anliegen von BioOK als ein multidisziplinäres wissenschaftliches Netzwerk ist die Entwicklung von maßgeschneiderten Ansätzen zur Risikoanalyse von GV Pflanzen auf der Grundlage von Ursache-Wirkungs­hypothesen mit dem Ziel des Aufbaus eines effektiven und qualifizierten Risikobewertungssystems. Die Forschungsaktivitäten von BioOK zielen auf einen Paradigmenwechsel im aktuellen Zulassungsprozess. Sie basieren auf einem modularen System, das alle Aspekte des Risikomanagements umfasst: molekulare Charakterisierung, Inhaltsstoffanalyse, agronomische Eigenschaften, Ziel- und Nichtzielorganismen, Boden und Mikroorganismen, Toxikologie, Allergenität und Überwachung nach Markt­einführung, wobei jeder Modul unterschiedliche Analysemethoden beinhaltet. Die durch BioOK angestrebte Reform des Risikobewertungsprozesses von GV Pflanzen umfasst zwei Phasen: zunächst die Optimierung der Analysemethoden selbst und dann die Etablierung eines Entscheidungsunterstützungssystems (Test Decision System – DSS), basierend auf biologischen Schwankungsbreiten (baselines), Zeigermerkmalen (indicators) und Grenzwerten (thresholds) für jede Analysemethode. BioOK hat in einer ersten Entwicklungsphase bereits optimierte Testmethoden entwickelt: Für die Inhaltsstoffanalyse wurde die Untersuchung auf substantielle Äquivalenz durch GC-MS, LC-MS und HPLC/RI Methoden vereinfacht. Ein neu eingeführtes Analyseschema zur Ermittlung potentieller Effekte von GV Pflanzen auf den Boden kombiniert ein in vitro System zur Beprobung von Rhizodepositaten von Pflanzen, die unter kontrollierten Umweltbedingen gewachsen sind, sowie die entsprechenden Bodentypen und deren Charakterisierung mit offenen und hochsensitiven molekular-chemischen Screening und Fingerprinting-Methoden. Ein neues in vitro System zur Simulation des Transports von Substanzen aus dem Darm ins Blut, das das Risiko der Aufnahme durch Mensch oder Tier zu einem frühen Zeitpunkt misst, wurde entwickelt. Um die Effektivität und Reproduzierbarkeit von Probenahmen an der Pflanze zu erhöhen, wird ein genau definiertes Probenahmeschema entwickelt. Schließlich, in Ergänzung der aktuellen Methodik zur Allgemeinen Überwachung (General Surveillance) von GV Pflanzen im Anbau, wurde eine Herangehensweise zur Abschätzung der Notwendigkeit für ein europaweites fallspezifisches (Case Specific) Monitoring beruhend auf Ursache-Wirkungsszenarien, erarbeitet. Die zweite Phase der BioOK F&E-Arbeiten konzentriert sich auf die Entwicklung eines Entscheidungsunterstützungssystems (Decision Support System, DSS). Dazu wird ein computergestütztes System implementiert, in dem alle standardisierten und validierten Methoden zu einem Entscheidungsbaum mit Knotenpunkten, definiert über biologische Schwankungsbreiten und potentielle Risiken definierenden Grenzwerten für Zeigermerkmale, zusammengeführt sind.    Genetically modified (GM) plants have to be analyzed for their potential impacts on the environment and on human or animal health before authorisation by the EU. The approval process currently refers to a conglomeration of diverse analytical methods and is intensive in time and costs. The intention of BioOK as a multidisciplinary scientific network is the development of tailor-made approaches for GM plants based on a cause-effect hypothesis to obtain an effective and qualified risk assessment system. The research activity of BioOK aims to renew the current approval process. It is based on a modular system covering all aspects of risk assessment: molecular characterisation, compound analysis, agronomic traits, target and non-target organisms, soil and micro organisms, toxicology, allergenicity and post-market monitoring, each module containing several test methods. The renewal of the risk assessment procedure intended by BioOK consists of two phases: first the optimization of test methods and second the establishment of a decision support system (DSS) based on baselines, indicators and thresholds developed for each of the methods. Optimized test methods have been developed mainly during the first phase: For compound analysis methods have been developed to ease the analysis of substantial equivalence of the events by GC-MS, LC-MS and HPLC/RI. A newly introduced testing scheme for the detection of potential effects of GM plants on soil combines an in-vitro system to collect rhizodeposits from plants grown under controlled environmental conditions and the correspon­ding bulk soil, and their characterisation by untargeted and highly sensitive molecular-chemical screening and fingerprinting technique. A novel in vitro system simula­ting the transport of substances from the gut into the blood that detects the risk of incorporation in human or animal at an early time point was developed. In order to increase the effectiveness and reproducibility of the sampling procedure we developed a valid defined sampling scheme. Finally, complementing the actual General Surveillance methodology, an approach for a Europe-wide case specific monitoring referring to cause-effect sce­narios was developed. The second phase concentrates on the development of a Decision Support System (DSS). A computer-based system will implement and merge all standardized methods in a decision tree system following decision rules defined by baseline and thresholds for indicators.   &nbsp