Showing papers in "Chemie Ingenieur Technik in 2013"

Production of Liquid Hydrocarbons with CO2 as Carbon Source based on Reverse Water-Gas Shift and Fischer-Tropsch Synthesis†

Abstract: The substitution of fossil fuels by renewable energy sources is needed to decrease greenhouse gas emissions, especially CO2. Wind and solar power are today considered as attractive alternatives for electric power generation, but are not suitable for providing base load. Thus, efficient storage of electrical energy is inevitable. Liquid hydrocarbons (HCs) exhibit an excellent volumetric energy density and offer various opportunities for storing electric energy. They can be produced by CO2 and renewable H2 (generated by water electrolysis) in a two step process. The first step is generation of syngas by reverse water-gas shift (RWGS) at elevated temperatures; the second step comprises the production of liquid hydrocarbons by Fischer-Tropsch (FT) synthesis. The experiments on RWGS with a commercial Ni-catalyst show that a CO2 conversion of around 80 % can be reached at 800 °C within a very short residence time of less than < 0.1 s. The experiments on FTS with Fe as catalyst and syngas containing different amounts of CO2 indicate that the influence of CO2 on CO conversion and product selectivities (including net CO2 production by water-gas shift) is insignificant if the inlet partial pressures of H2 and CO are kept constant. If CO is substituted by CO2, less HCs are formed, the water-gas shift is repressed, and methane selectivity increases.

Abgasnachbehandlung in mobilen Systemen: Stand der Technik, Herausforderungen und Perspektiven

Abstract: Eine ganzheitliche Betrachtungsweise von Abgasnachbehandlungssystemen ist derzeit der attraktivste Ansatzpunkt fur die weitere Verminderung der Schadstoffemissionen und um auf neue Herausforderungen durch strengere Emissionsgrenzwerte, neue Rohstoffbasis und effektivere Motorkonzepte schneller zu reagieren. Dieser Artikel gibt einen Uberblick zu gegenwartigen Abgasnachbehandlungssystemen. Heutige und zukunftige Herausforderungen und Ansatze zu deren Bewaltigung werden diskutiert. Bei den vorgestellten Losungsansatzen spielen hierarchische Modellierung von DFT-Berechnungen bis zur CFD-Simulation des kompletten Abgasstranges, realitatsnahe Abgasprufstande und Alterungsverfahren sowie On-board-Diagnostik ebenso wie die Charakterisierung von Katalysatoren insbesondere unter Reaktionsbedingungen sowie moglichst alle Langenskalen eine wichtige Rolle. In Zukunft werden wissensbasierte roboter-kontrollierte Praparation und dynamische Modelle, gekoppelt mit Informationen aus dem realen Betrieb, Forschung und Entwicklung masgeblich unterstutzen.

Bioengineering Parameters for Single‐Use Bioreactors: Overview and Evaluation of Suitable Methods

Abstract: During the past five years, the number of single-use bioreactors used in biopharmaceutical research and production has increased tremendously. This increase has been particularly associated with mammalian cell culture processes from small- to medium-scale volumes. Even though nowadays customers can choose from a multitude of 2nd and 3rd generation single-use bioreactors, ranging from mL- up to m3-scale, there is a lack of knowledge of their engineering parameters. Different approaches have been applied to characterization investigations, resulting in an inability to compare different single-use bioreactors with each other and their reusable counterparts, creating an obstacle to a systematic approach to scaling-up the process. This article describes parametric, experimental and computer-based numeric methods for biochemical engineering characterization of single-use bioreactors, which have already been used successfully for the characterization of their reusable counterparts. For the first time, these methods have been evaluated in terms of their practical application.

Fluid Flow and Cell Proliferation of Mesenchymal Adipose-Derived Stem Cells in Small-Scale, Stirred, Single-Use Bioreactors

Abstract: The fluid flow and suspension characteristics inside small-scale, stirred, single-use bioreactors were investigated experimentally and by means of computational fluid dynamics. The required impeller speeds for homogenous suspension were determined for two microcarrier types. The shear stress level and turbulence distribution were predicted using a numerical model, which was verified by particle image velocimetry measurements. In subsequent cultivations of primary mesencymal adipose-derived stem cells, up to 31.4-fold expansion in cell number was achieved for serum concentrations as low as 5 %.

Integrated Clinical Scale Manufacturing System for Cellular Products Derived by Magnetic Cell Separation, Centrifugation and Cell Culture

Abstract: Manufacturing of cellular products for therapeutic purposes like stem cell or cancer therapy requires equipment with specific characteristics not always addressed by conventional technologies. A new integrated cell processing device is presented that can handle all current technical requirements for manufacturing cellular products by automation of the complete process in a GMP-compliant single-use tubing set. Its capabilities are exemplified in the presented study by successful processing of adult stem cells, natural killer cells, and several cell lines. Multiple cell processing workflows can be automated in a functionally closed environment: from cell separation through cell culture to formulation of the final product.

hMSC Production in Disposable Bioreactors with Regards to GMP and PAT

Abstract: Reactor concepts for human mesenchymal stem cell (hMSC) production are introduced Thereby, special interest is laid on the realization of these concepts as disposables fulfilling the GMP and PAT requirements The specialty of the hMSC production process is the cell itself being the product This results in completely different process requirements compared to eg protein production in mammalian cells Thus, great attention has to be given to the shear sensitivity of the cells The cultivation and the harvest of the cells have to be very gentle to neither influence cell viability nor cell differentiability Further, the production process should not cause any undesirable cell changes For hMSC production, cell harvest is the main challenging process step The reactor concepts should be suitable for hMSC production for clinical trials as ATMPs Therefore, disposable systems are especially applicable The review describes more detailed bone marrow-derived hMSC production in a disposable stirred tank reactor as promising reactor concept

Ammonia Recovery from Industrial Wastewater by TransMembraneChemiSorption

Abstract: Membrane technology is a growing alternative for ammonia removal and recovery from wastewater compared to many other water treatment processes, such as strippers, scrubbers, and deaeration systems. Among the available alternatives, the TransMembraneChemiSorption (TMCS) has been gaining consideration, especially under certain operating conditions. TMCS using a membrane contactor is a unique separation process that is transitioning from research and pilot phases to field installations. This paper reviews the results of such an ammonia removal system using membrane contactors.

Omix – A Visualization Tool for Metabolic Networks with Highest Usability and Customizability in Focus

Abstract: Visualization has become indispensable in the analysis and interpretation of data from experiment and simulation. To adequately represent the diversity of studied phenomena, it is necessary to support researchers with tools that are easy to use and allow effective data visualization with special regard to individual requirements. This contribution presents the visualization tool Omix, an editor for metabolic network diagrams and a customizable visualization framework. As an outstanding feature, data visualization is script-based. The dedicated new scripting language OVL (Omix Visualization Language) enables the user to freely design the manner data is visualized in the network. An intuitive user interface, several newly developed, domain-specific drawing automatisms as well as visualization concepts make the software Omix a mature computational tool supporting the specific requirements of researchers from systems biology and life science domains as will be demonstrated on several application examples.

Heterogen katalysierte Hydrierung von Kohlendioxid zu Methan unter erhöhten Drücken

Abstract: In der vorliegenden Arbeit wurden vor allem Ni- und Ru-haltige Tragerkatalysatoren synthetisiert und fur die Hydrierung von Kohlendioxid zu Methan (Sabatier-Reaktion) gepruft. Im Mittelpunkt der Untersuchungen standen Versuche zum Einfluss von Reaktionstemperatur und -druck. Als sehr geeignete Tragermaterialien erwiesen sich ZrO2 und γ-Al2O3, die im Temperaturbereich von 300 – 400 °C hohe CO2- und H2-Umsatze (70 – 80 %) und Methan-Selektivitaten uber 99 % erlauben. Im Gegensatz dazu fuhrten TiO2- und SiO2-basierte Katalysatoren fast ausschlieslich zu CO und scheinen fur die Reaktion nicht geeignet. Die Untersuchungen zur Druckabhangigkeit zeigten eindrucksvoll den Einfluss auf die Lage des chemischen Gleichgewichts. Die CO2- und H2-Umsatze lagen an einem Ru/ZrO2-Katalysator oberhalb 95 % und Methan wurde mit einer Selektivitat von &n62; 99,9 % gebildet. Ni- and Ru-containing supported catalysts were prepared and used for the CO2 hydrogenation to methane (Sabatier reaction) in the gas phase. Tests on the effect of the reaction temperature and pressure were in the focus. ZrO2 and γ-Al2O3 were used as suitable catalyst supports. CO2 and H2 conversions of 70 – 80 % and selectivity to methane of &n62; 99 % were reached. TiO2 and SiO2 based catalysts exclusively lead to CO and seem to be not suited for this reaction. The investigations on the pressure effect impressively demonstrated the influence on the chemical equilibrium. CO2 and H2 can be nearly completely converted with &n62; 99.9 % selectivity to methane over Ru/ZrO2.

Gamma‐Ray Computed Tomography for Imaging of Multiphase Flows

Abstract: Multiphase flows are omnipresent in the chemical industry. The flow phenomena in multiphase reactors strongly affect the processes performance. Nonetheless, even basic information on flow patterns, flow regimes and effects of internals etc. is often not available, which is a strong obstacle for a reliable design and scale-up. Non-invasive tomographic techniques are promising measurement tools to visualize opaque multiphase flows. The contribution provides a short survey about today's tomographic imaging techniques and introduces the principles of radiation-based tomography. In particular, two gamma-ray computed tomography designs and their application for sparger performance study in large bubble columns and for flow regime determination in inclined rotating fixed-bed reactors are presented.

Disposable Flat Panel Airlift Photobioreactors

Abstract: Single-use technology based on disposable bioreactors is gaining more and more importance in biotechnology due its high flexibility, easy handling and ready-to-use character when supplied. A disposable, low-cost, transparent flat panel airlift photobioreactor with optimized flow regime for the efficient cultivation of microalgae and production of microalgal metabolites is presented and possible applications are discussed.

Cultivation of Cells and Microorganisms in Wave-Mixed Disposable Bag Bioreactors at Different Scales

Abstract: Disposable bioreactors have gained an increasing importance in recent years in the pharmaceutical production. Wave-mixed reactors were among the first systems which were applied. In contrast to stirred tank reactors, wave-mixed bioreactors are characterized by low shear forces while the gas exchange is realized by the large gas-liquid interface. Oxygen transfer rates obtained are often in a range between 50 and 300 h–1. By applying nutrient-limiting fed-batch cultivations, in which the oxygen consumption of a culture is controlled, bacteria can be also cultivated in wave-mixed reactors. This article describes the successful scale-up of an Escherichia coli fed-batch cultivation from the 12-L to the 120-L scale using a disposable bioreactor, in which a final biomass concentration of 45 g L–1 was obtained.

Holdup and Pressure Drop in Micro Packed-Bed Reactors for Fischer-Tropsch Synthesis

Abstract: Low-temperature Fischer-Tropsch synthesis was investigated in micro packed-bed reactors. Co/Re/c-Al2O3 catalysts with different particle shapes and sizes (60 to 580 lm) were employed. Tubular reactor geometry with lengths of up to 1 m was chosen. Pressure drop measurements in the absence of reaction and during reaction were carried out. For analysis of the experimental data a reactor model was developed, which was also used for the determination of liquid holdup. It could be observed that the liquid holdup is independent of conversion, reaction temperature, C5+ productivity, and reaction rate. For irregularly shaped catalyst particles, a liquid holdup in the range of 3 % was observed.

Theoretical and Experimental Investigations of Flat Sheet Membrane Module Types for High Capacity Gas Separation Applications

Abstract: Gas permeation is increasingly considered for high capacity applications. This contribution discusses the commonly employed membrane module types for flat sheet membranes and suggests a new module concept. The applications considered are the separation of CO2 from flue gas and hydrocarbon dewpointing of natural gas. Rigorous models for predicting the operating performance of the module types are described. Pilot plant experiments were conducted to validate the model for envelope type modules. Simulation studies were carried out to predict the performances of the different module types for the two examples and assess their advantages and disadvantages.

Effect of Phosphate Modification on the Brønsted Acidity and Methanol‐to‐Olefin Conversion Activity of Zeolite ZSM‐5

Abstract: Phosphate-modified ZSM-5 zeolites were studied by standard characterization techniques and solid-state nuclear magnetic resonance spectroscopy, and in the methanol-to-olefin (MTO) conversion. Considering the physicochemical properties of the ZSM-5 zeolites, the most important effects of the phosphate modification are a deposition of polyphosphates in the pore system and a decrease of the acid site density, but not of the acid site strength. The significant increase in the selectivity to C2 – C4 alkenes and the decrease of C5+ formation in the MTO reaction for a phosphate coverage of about 5 wt % are explained by extra-framework phosphate species near the crossing intersections of the ZSM-5 pore system, which hinder the formation of large intermediates and reaction products.

Numerical Simulation of Polydispersed Flow in Bubble Columns with the Inhomogeneous Multi‐Size‐Group Model

Abstract: The present paper shows the influence of considering polydispersity of bubbly flow, simulating bubble columns with a three-dimensional Eulerian two-fluid model A complete set of interfacial closure models regarding drag force, lift force, wall force, turbulent dispersion force and bubble-induced turbulence is considered A round bubble column of 0288 m diameter and 25 m height is simulated up to a superficial gas velocity of 1 cm s–1 and compared with experimental data It is shown that considering the polydispersity including the non-drag forces, important flow properties of bubble columns are reproduced Possible influences of swarm effects on the non-drag forces are discussed and needs for further investigations are given

Comparison of Two-Fluid and Discrete Particle Modeling of Dense Gas-Particle Flows in Gas-Fluidized Beds

Abstract: Both two-fluid models embedding the kinetic theory of granular flow for particulate phase stress (TFM) and discrete particle models (DPM) are widely used for the numerical simulation of gas fluidization. In this study, a detailed comparison between results obtained from both TFM and DPM is reported, including axial and radial solid concentration profiles, solids circulation patterns, pressure drop and its standard deviation and granular temperature. It was shown that good agreement can be obtained even in cases of low restitution coefficient, which suggests the possible applicability of kinetic theory of granular flow beyond its nominal range of validity and clearly indicates that the continuum treatment of the solids phase in TFM provides a good approximation of its discrete nature.

Optical Multimode Online Probe: Erfassung und Analyse von Partikelkollektiven

Abstract: Die vorgestellte Optical Multimode Online Probe verwendet telezentrische Beleuchtung mittels Hochleistungs-Mikro-LED (493 lm) und ein objektseitig-telezentrisches Objektiv zur Online-Analyse von Tropfenkollektiven. Es entstehen relative Messfehler von < 2 – 5 % (Durchlicht) bzw. <60; 12 % (Auflicht) bezogen auf die Partikeldurchmesser. Aufbauend auf der Distanztransformation zur Analyse der Durchlichtabbildungen wird ein adaptiver Vorsegmentierungsansatz auf Basis des Random Forest Classifiers vorgestellt. Die Abweichungen bezogen auf die Pixelzahl liegen bei 1 bis 6 %, nach Auswertung der Kreise bei 12,9 % bezogen auf den mittleren Partikeldurchmesser. The presented optical multimode online probe uses telecentric illumination with a high performance micro LED (493 lm) and objectspace-telecentric objective to analyze particles online and in situ. The relative measurement errors are between <60; 2 – 5 % (transmitted light) and below 12 % (incident light, with regard to the particle diameter). The distance transform approach for transmitted-light images is extended for the analysis of diffuse incident-light images by an adaptive pre-segmentation approach based on the random forest classifier algorithm. The error with regard to the pixel number is typically between 1 to 6 %, while the evaluation of particle diameters gives deviations up to 12.9 %.

Einsatz eines Blasensäulenreaktors zur Methansynthese

Abstract: Bei der Methanisierung ist eine effektive Abfuhr der Reaktionswarme eine zentrale Herausforderung. Die Dreiphasen-Methanisierung ist unter diesem Aspekt durch einfach zu gestaltende Energieabfuhr und Temperaturregelung vorteilhaft und erlaubt eine isotherme Fahrweise. Durch die hohe Warmekapazitat der Suspensionsflussigkeit kuhlt der Reaktor langsam aus und bietet sich daher fur die Power-to-Gas (PtG) Prozesskette mit ihrer schwankenden Eduktgas-Bereitstellung an. Verschiedene Flussigkeiten und Betriebsbedingungen wurden bezuglich ihrer Eignung fur die Dreiphasen-Methanisierung untersucht. The high reaction heat of the methanation reaction requires an effective heat removal. For this purpose a three-phase reactor could be advantageous as the heat can easily be removed by external heat exchangers. Moreover, the temperature control is simplified, and the reactor can be operated isothermal. Especially for the Power-to-Gas process a three-phase reactor is very promising. Due to the high heat capacity of the liquid phase, it cools down slowly and hence buffers the effect of fluctuating feed stream. The applicability of several liquids and different operating conditions for three-phase methanation was investigated.

High Cell Density Escherichia coli Cultivation in Different Single-Use Bioreactor Systems

Abstract: During the last decades single-use bioreactors have become widely accepted in the biopharmaceutical industry. Single-use technologies bring many advantages over conventional solutions, such as a reduced investment and operational cost as well as an optimized time-to-market. So far, this type of bioreactor is mainly used for cell culture applications. Results for microbial fermentations are rarely found, commonly due to limited oxygen transfer rates. The aim of this study was to establish a high cell density fermentation process for a recombinant Escherichia coli considering a rocking motion type and an adapted stirred 50-L single-use bioreactor. By using the design space approach an OTRmax/OURmax model was established. The feeding strategies were optimized and verified based on a model for both single-use systems to achieve high cell densities. In both single-use bioreactors a recombinant protein was successfully expressed.

An Approach for Scale-Up of Geometrically Dissimilar Orbitally Shaken Single-Use Bioreactors

Abstract: An initial approach for scaling up geometrically dissimilar orbitally shaken bioreactors is presented. A novel ShakerBag Option for Multitron Cell shaking incubators allows a rapid increase in working volume from small TubeSpin bioreactors or shake flasks up to 10 L, thus offering a simple and cost-efficient alternative to present systems for scale-up. The engineering parameters for scale-up of the orbitally shaken single-use bags were determined using traditional methods. Modern computational fluid dynamics based methods were used to gain a deeper insight into the fluid flow behavior. Furthermore, mass propagation of plant cell suspensions (Nicotiana tabacum and Vitis vinifera), as well as cell expansion and production of protein complexes using insect cells (Sf-9), show the potential of orbitally shaken single-use bags.

Poly(propylencarbonat) aus Kohlendioxid: Herausforderungen für eine großtechnische Umsetzung

Abstract: Der Stand der Technik bei der Herstellung von Poly(propylencarbonat) ausgehend von Propylenoxid und Kohlenstoffdioxid wird vorgestellt. Thermodynamisch betrachtet ist Poly(propylencarbonat) ein kinetisches Produkt mit einer hohen Bildungsenthalpie. Nach jahrzehntelangen Entwicklungen sind einige vielversprechende Katalysatoren gefunden worden, die eine kostengunstige Herstellung ermoglichen konnten. Ein kontinuierliches Verfahren wurde kurzlich patentiert. Die verbleibenden Herausforderungen fur eine grostechnische Umsetzung bestehen darin, ein einfaches Verfahren zu finden und die Materialeigenschaften fur bestehende Anwendungen maszuschneidern. The state of the art in the preparation of poly(propylene carbonate) from propylene oxide and carbon dioxide is summarized. Poly(propylene carbonate) is a kinetic product with a high enthalpy of formation. After decades of continuous development catalysts are now available that would allow an economically viable preparation of the polymer. A continuous process was patented recently. The remaining challenges for an economically successful large-scale application are to establish a simple process and to adjust the material property profile to requirements of existing markets.

Screening of Porous Materials by Thermal Response Measurements

Abstract: Adsorption thermal response screening by optical adsorption calorimetry was recently demonstrated to be a versatile tool for rapid surface area and adsorption capacity testing of porous materials. Beyond the high throughput approach, further insight in possibilities and application examples for the method will be presented. Especially a rapid classification of porous materials regarding their pore properties and the possibility to evaluate adsorption kinetics by using thermal response measurements will be discussed.

Titanium Carbide and Carbide‐Derived Carbon Composite Nanofibers by Electrospinning of Ti‐Resin Precursor

Abstract: TiO2/C and TiC/C composite nanofibers were produced by electrospinning of resin/TiCl4 precursor solution. The resulting ceramic fiber webs were porous and showed surface areas as high as 523 m2g–1. They were further converted to carbide-derived carbon (CDC) fibers under full retention of the fiber-like shape and flexibility. These CDC membranes showed a hierarchical pore structure and specific surface as high as 1378 m2g–1. Applications in the area of high temperature filtration, catalyst support and energy storage are conceivable.

Metal Organic Frameworks for Natural Gas Storage in Vehicles

Abstract: With the increasing demand for alternative fuels the storage of natural gas (NG) in adsorbents like metal organic frameworks (MOFs) will become more important. In order to use MOFs as storage media in fuel delivery systems, the optimization of mass and energy transfer of the system is crucial. For rapid NG filling of a tank, molecules need to reach the adsorption sites within a reasonable time while the heat of adsorption should be dissipated to the environment. In this article, mass transfer in shaped bodies of MOFs was determined by permeability measurements and pulsed field gradient (PFG) NMR spectroscopy. The heat dissipation was also experimentally measured and both data sets were used to set up a theoretical density function theory model to predict the behavior of MOFs for NG storage.

Bioprocess Development in Single-Use Systems for Heterotrophic Marine Microalgae

Abstract: The utilization of single-use systems is more and more common in upstream cultivation in biotechnological processes. The advantages of single-use bioreactors for the cultivation of the heterotrophic microalgae Crypthecodinium cohnii serves as an example for the feasibility of polymer based orbital shaken systems for shear-sensitive microorganisms with a high oxygen demand. Experiments in the shake flask scale indicate the advantage of tubes like the TubeSpin Bioreactor 600 in comparison to standard Erlenmeyer flasks. In the screening stage, performed in orbitally shaken deepwell plates, the growth performance is significantly improved by the application of perflourodecalin for the modulation of the gas transfer. The use of orbitally shaken systems from the deepwell plate format over the TubeSpin towards orbitally shaken bioreactors provides a reliable strategy for the consistent bioprocess development and scale up of shear-sensitive aerobic microorganisms. The consistent scalability of the process up to 200 L is envisaged.

75 Jahre Hydroformylierung – Oxoreaktoren und Oxoanlagen der Ruhrchemie AG und der Oxea GmbH von 1938 bis 2013

Abstract: Die Hydroformylierung, auch als Oxosynthese oder Roelen-Reaktion bezeichnet, ist die atomokonomische und metallkatalysierte Addition der Bestandteile des Synthesegases, H2 und CO, an die Doppelbindungen von Alkenen. Sie wurde 1938 von Otto Roelen in den Laboratorien der Ruhrchemie AG entdeckt. Die Bemuhungen zur Ubertragung des Verfahrens in den technischen Masstab begannen sofort nach der Patentanmeldung. Sie fuhrten aber wahrend des 2. Weltkrieges und den dadurch bedingten schwierigen Umstanden nur zu einem Teilerfolg in den Anlagen der Ruhrchemie AG Oberhausen-Holten und des Kooperationspartners, der I.G. Farbenindustrie AG. Nach dem 2. Weltkrieg wurden das Ruhrchemie-Verfahren auf der Basis von Kobaltkatalysatoren und das Ruhrchemie/Rhone-Poulenc-Verfahren als erstes technisch wichtiges, wassriges Zweiphasenverfahren mit Rhodiumkatalysatoren zu fuhrenden homogen katalysierten Prozessen der Chemie. The hydroformulation reaction, also known as oxo synthesis or Roelen reaction, is the atom-efficient and metal-catalyzed addition of the constituents of synthesis gas, H2 and CO, to the double bonds of alkenes. This reaction has been discovered in 1938 by Otto Roelen in the laboratories of the chemical company Ruhrchemie AG. After filing the patent application efforts to scale up the process to technical scale have been started. However, they have only partly been successful for the plants of the Ruhrchemie AG Oberhausen and its cooperation partner I.G. Farbenindustrie AG due to the difficult circumstances. After World War II the Ruhrchemie process based on cobalt catalysts and the Ruhrchemie/Rhone-Poulenc process as the first important aqueous two-phase processes with rhodium catalysts became the most important homogenously catalyzed chemical processes.

Katalytische Funktionalisierungen von Oleylalkohol in thermomorphen Lösungsmittelsystemen zur Synthese potenzieller Biotenside und ‐Monomere

Abstract: Es werden zwei Funktionalisierungen des Oleylalkohols vorgestellt, die interessante Produkte fur Anwendungen als Tenside und Biopolymere zuganglich machen. Die Tandemreaktion Hydroaminomethylierung konnte fur das Amin Diethylamin mit hohen Ausbeuten optimiert werden. Die Hydroesterifizierung zeigt hohe Ausbeuten fur verzweigte Hydroxyester. Es wird auserdem eine Trennung von Produkten und Katalysatoren in einem thermomorphen Losungsmittelsystem gezeigt. Aufgrund der mittelpolaren Produkte zeigen sich aber hohe Leachingwerte in den Produktphasen. Two functionalizations of the unsaturated fatty alcohol oleylalcohol with carbon monoxide via the homogeneous catalyzed reactions hydroaminomethylation and hydroesterification are shown. In this way it is possible to gain new biosurfactants and biopolymers. The tandem reaction hydroaminomethylation was optimized to high yields for adducts with diethylamine. Hydroesterification of oleylalcohol showed high yields for the hydroxyl esters. An approach for separation of catalyst and products by employing a thermomorphic solvent system is presented.

Biocatalytic Production of Chemical Building Blocks in Technical Scale with α-Ketoglutarate-Dependent Dioxygenases

Abstract: Due to the low reactivity of CH bonds and often low regio- and stereoselectivities, CH activations rank among the most challenging reactions in synthetic organic chemistry. In contrast, in nature CH functionalizations are integral part of numerous biosyntheses, especially of secondary metabolites. In aerobic organisms these reactions are typically catalyzed by oxygenases, among which the cytochrome P450 monooxygenases are the most prominent. A second large group are the α-ketoglutarate- (αKG) dependent dioxygenases, whose enormous synthetic potential has been discovered only recently. Although the utilization of oxygenases for organic synthesis is most desirable, their technical application is limited, because they are usually difficult to process. With αKG-dependent dioxygenases some of the problems can be reduced or even avoided. In this article some prominent examples for approaches with αKG-dependent dioxygenases are reviewed and efforts to engineer a deacetoxycephalosporin synthase are discussed.

Investigations on Mechanical Stress Caused to CHO Suspension Cells by Standard and Single‐Use Pumps

Abstract: Mechanical stress caused to transfected Chinese hamster ovary (CHO) suspension cells by reusable and single-use magnetically levitated, bearingless centrifugal pumps was investigated. Cell death rates were determined for different pump speeds and compared with data from a peristaltic and a 4-piston diaphragm pump. Furthermore, the fluid distribution inside the PuraLev® 200 pump was modeled using computational fluid dynamics. The results reveal considerably lower mechanical stress to CHO cells caused by the magnetically levitated bearingless centrifugal pumps than by the peristaltic and diaphragm pump.