41 research outputs found
Lattice Boltzmann Modeling-based Design of a Membrane-free Liquid-liquid Microseparator
The benefits of continuous processing and the challenges related to the integration with efficient downstream units for end-to-end manufacturing have spurred the development of efficient miniaturized continuously-operated separators. Membrane-free microseparators with specifically positioned internal structures subjecting fluids to a capillary pressure gradient have been previously shown to enable efficient gas-liquid separation. Here we present initial studies on the model-based design of a liquid-liquid microseparator with pillars of various diameters between two plates. For the optimization of in silico separator performance, mesoscopic lattice-Boltzmann modeling was used. Simulation results at various conditions revealed the possibility to improve the separation of two liquids by changing the geometrical characteristics of the microseparator.
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Implementation of Microreactor Technology in Biotechnology – IMTB Conference: A new platform for an interdisciplinary science and technology
Separation and purification of biomacromolecules based on microfluidics
Separation and purification of biomacromolecules either in biopharmaceuticals and fine chemicals manufacturing, or in diagnostics and biological characterization, can substantially benefit from application of microfluidic devices. Small volumes of equipment, very efficient mass and heat transfer together with high process control result in process intensification, high throughputs, low energy consumption and reduced waste production as compared to conventional processing. This review highlights microfluidics-based separation and purification of proteins and nucleic acids with the focus on liquid-liquid extractions, particularly with biocompatible aqueous two-phase systems, which represent a cost-effective and green alternative. A variety of microflow set-ups are shown to enable sustainable and efficient isolation of target biomolecules both for preparative, as well as for analytical purposes.publishe
Modelling of L-DOPA Oxidation Catalyzed by Laccase
Enzymatic oxidation of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) with laccase from Trametes versicolor was investigated. The highest enzyme activity at pH 5.4 and at 25 ºC was found. The reaction kinetics and the effect of dissolved oxygen concentration on the reaction rate were evaluated. A mathematical model, comprised of double-substrate Michealis-Menten kinetics and mass balances for L-DOPA and dissolved oxygen concentrations, was developed in order to describe and predict the process of L-DOPA oxidation. Kinetic parameters, , and were estimated and experimentally verified by a set of experiments with constant additional aeration for different initial concentrations of L-DOPA and dissolved oxygen. A significant increase in reaction rate was established at a higher oxygen concentration in the inlet gas. The developed model was used to investigate the influence of dissolved oxygen concentration on L-DOPA conversion
The Effect of Enzymatic Treatments of Pulps on Fiber and Paper Properties
Biotechnological treatment of pulps provides great potential for the reduction of energy consumption and greenhouse gas emissions. In the present work, the influence of different commercial cellulases and xylanases or their mixtures on the quality of different bleached kraft pulps was investigated. The effects of enzymes on reducing sugars release and changes in fiber length were assessed for 3 different eucalyptus pulps, for a pulp consisting of a mixture of hardwoods and for softwood pulp. Despite the extremely high
enzyme concentrations used in this part of the study, almost no change in fiber length was observed for pulps treated with enzyme preparations alone, while all combinations of cellulases and xylanases resulted in significant changes in average fiber length, portion of fines and reducing sugars release. Besides, vessel cell deformation was observed as a consequence of all enzymes applications. Furthermore, physical and mechanical properties of laboratory sheets made with enzymatically treated pulps were evaluated for various refining conditions and compared to those of untreated pulps. Potential energy savings up to 17 % were achieved with enzyme treatment, but some decrease in pulp quality was also observed
Evaluation of Diffusion Coefficient Determination using a Microfluidic Device
A theoretical description of the convection-diffusion process in a homogeneous system enabling estimation of diffusion coefficients employing commercially available Y-junction microchannel is presented. A detailed numerical analysis based on finite volumes and finite differences, namely the explicit, implicit and Crank-Nicolson method, was performed and analyzed on the same domain in order to verify the proposed models. All numerical approaches provided stable solutions with certain numerical variations depending on the number of iterations defined by the mesh density. In addition, the method
was validated with measurements of diffusion coefficients of some selected components in the short Y-junction microchannel. Benefits and possible pitfalls of this estimation method are discussed