Monitoring gradient formation in a jet aerated bioreactor.

Jet aerated loop reactors (JLRs) provide high mass transfer coefficients (ka) and can be used for the intensification of mass transfer limited reactions. The jet loop reactor achieves higher ka values than a stirred tank reactor (STR). The improvement relies on significantly higher local power inputs (∼10) than those obtainable with the STR.

Impact of nozzle operation on mass transfer in jet aerated loop reactors. Characterization and comparison to an aerated stirred tank reactor.

The impact of mass transfer on productivity can become a crucial aspect in the fermentative production of bulk chemicals. For highly aerobic bioprocesses the oxygen transfer rate (OTR) and productivity are coupled. The achievable space time yields can often be correlated to the mass transfer performance of the respective bioreactor.

Jet aeration as alternative to overcome mass transfer limitation of stirred bioreactors.

In industrial biotechnology increasing reactor volumes have the potential to reduce production costs. Whenever the achievable space time yield is determined by the mass transfer performance of the reactor, energy efficiency plays an important role to meet the requirements regarding low investment and operating costs. Based on theoretical calculations, compared to bubble column, airlift reactor, and aerated stirred tank, the jet loop reactor shows the potential for an enhanced energetic efficiency at high mass transfer rates.

Data-based optimization of protein production processes.

While data-based modeling is possible in various ways, data-based optimization has not been previously described. Here we present such an optimization technique. It is based on dynamic programming principles and uses data directly from exploratory experiments where the influence of the adjustable variables u were tested at various values.

Production of polyomavirus-like particles in a Klgal80 knockout strain of the yeast Kluyveromyces lactis.

VP1, the major coat protein of polyomavirus, assembles intracellularly to virus-like particles if expressed in eukaryotes. Here, the nonconventional yeast Kluyveromyces lactis was used for production of virus-like particles of murine polyomavirus. The heterologous gene of VP1 was integrated in the LAC4 locus of the GAL/LAC genes.

Increasing batch-to-batch reproducibility of CHO-cell cultures using a model predictive control approach.

By means of a model predictive control strategy it was possible to ensure a high batch-to-batch reproducibility in animal cell (CHO-cell) suspensions cultured for a recombinant therapeutic protein (EPO) production. The general control objective was derived by identifying an optimal specific growth rate taking productivity, protein quality and process controllability into account. This goal was approached indirectly by controlling the oxygen mass consumed by the cells which is related to specific biomass growth rate and cell concentration profile by manipulating the glutamine feed rate.

Simplified off-gas analyses in animal cell cultures for process monitoring and control purposes.

Batch-to-batch reproducibility of animal cell cultures can significantly be enhanced using process control procedures. Most informative signals for advanced process control can be derived from the volume fractions of oxygen and carbon dioxide in the vent line of the reactors. Here we employed simple low-cost sensors, previously not considered for off-gas analysis at a laboratory-scale cell cultures, and compared them with a simultaneously used quadrupole mass spectrometer, i.

Simple control of fed-batch processes for recombinant protein production with E. coli.

A very simple but effective process control technique is proposed that leads to a high batch-to-batch reproducibility with respect to biomass concentration as well as the specific biomass growth rate profiles in E. coli fermentations performed during recombinant protein production. It makes use of the well-established temperature controllers in currently used fermenters, but takes its information from the difference between the controlled culture temperature T (cult) and the temperature T (coolin) of the coolant fed to the fermenter's cooling jacket as adjusted by the fermenter temperature controller.