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Article
Improving cultivation processes for recombinant protein production
An new cascade control system is presented that reproducibly keeps the cultivation part of recombinant protein production processes on its predetermined track. While the system directly controls carbon dioxide...
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Article
Increasing batch-to-batch reproducibility of CHO cultures by robust open-loop control
In order to guarantee the quality of recombinant therapeutic proteins produced in mammalian cell systems, the straightforward approach in industry is to run the processes as reproducible as possible. It is fir...
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Article
A test facility for fritted spargers of production-scale-bioreactors
The production of therapeutic proteins requires qualification of equipment components and appropriate validation procedures for all operations. Since protein productions are typically performed in bioreactors ...
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Article
Comparison of viable cell concentration estimation methods for a mammalian cell cultivation process
Various mechanistic and black-box models were applied for on-line estimations of viable cell concentrations in fed-batch cultivation processes for CHO cells. Data from six fed-batch cultivation experiments wer...
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Article
Simple adaptive pH control in bioreactors using gain-scheduling methods
A simple well-performing adaptive control technique for pH control in fermentations of recombinant protein production processes is described and its design procedure is explained. First, the entire control alg...
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Article
Advanced control of dissolved oxygen concentration in fed batch cultures during recombinant protein production
Design and experimental validation of advanced pO2 controllers for fermentation processes operated in the fed-batch mode are described. In most situations, the presented controllers are able to keep the pO2 in fe...
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Article
Spontaneous condensation in DNA-polystyrene- b-poly(l-lysine) polyelectrolyte block copolymer mixtures
We investigated the condensation of calf thymus DNA by amphiphilic polystyrenem-b-poly(l-lysine)n block copolymers ( PS m -b- PLys n , m, n = de...
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Article
Hybrid process models for process optimisation, monitoring and control
Hybrid models aim to describe different components of a process in different ways. This makes sense when the corresponding knowledge to be represented is different as well. In this way, the most efficient repr...
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Chapter
Dynamics of the Flow in Bubble Column Reactors
Bubble columns are modelled by means of an Euler-Langrange-type model based on the Navier-Stokes equation system. It is shown that the model cannot only be used to describe typical situations in the bubble col...
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Article
Model-based optimization of viral capsid protein production in fed-batch culture of recombinant Escherichia coli
An optimized fed-batch cultivation process for the production of the polyoma virus capsid protein VP1 in recombinant Escherichia coli BL21 bacteria is presented. The optimization procedure maximizing the amount ...
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Article
Model based calculation of substrate/inducer feed-rate profiles in fed-batch processes for recombinant protein production
A model-based feed-rate profile optimization problem is discussed for the fed-batch recombinant protein production. Two optimization procedures, an evolutionary programming technique and a simplified method us...
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Article
Model based design of a biochemical cultivation process
In this paper a simple design procedure is used to enhance the performance of a biotechnical cultivation process. A model supported approach is proposed. It starts with a simple classical process model obtain...
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Article
Model-based design of biochemical processes: simulation studies and experimental tests
A simple design procedure is proposed that can be used to enhance the performance of a biological cultivation process. The model-supported method starts with a simple model. This is used to design first experi...
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Article
Automatic control of the specific growth rate in fed-batch cultivation processes based on an exhaust gas analysis
A new simple strategy for a reliable and robust automatic control of the specific growth rate in fed-batch cultivation processes is presented. Its advantages over model supported control is that the algorithm ...
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Article
Interpretation of the gas residence time distributions in large stirred tank reactors
The behaviour of dispersed gas in large aerated stirred tank reactors is modelled by means of a Markov-process, which distinguishes between small recirculation bubbles with “stagnant gas” content, large rising...
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Article
Interpretation of gas residence time distributions in large airlift tower loop reactors
Gas-residence time distribution (RTD) response curves measured in a 23 m high pilot plant airlift tower loop reactor, which consisted of a riser, a special downcomer construction and at the top of the riser a ...
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Chapter
Improvement of the Penicillin Production in Bench-Scale Reactors by On-Line Measurement, Data Evaluation and Parameter-Adaptive Control
Penicillin V was produced in a 40 L volume stirred-tank (ST) and in a 100 L volume airlift tower loop (AL) reactor with Penicillium chrysogenum S2 in fed-batch operation. Concentration...
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Chapter
On Experiences with Expert Systems in the Control of Bioreactors
We describe a system which has been built to process knowledge about biotechnological processes aiming to enhance the performance of the automatic control of a specified process.
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Article
Simple measuring techniques for the determination of bubble- and bulk-phase velocities in bioreactors
Ultrasound Doppler pulse velocimetry for the measurement of bubble velocities and local temperature pulse time-of-flow techniques for determining the flow velocities of the liquid phase are two complementary n...
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Chapter
Turbulence Measurements in Bubble Columns
Most problems in the design and performance prediction of bubble column reactors appear, because it is — up to now — not possible to control the fluid dynamics in such reactors. Especially the parameters of th...
