Bioprocess Laboratory BPL

Prof. Sven Panke

BPL topics revolve around the central theme of integrating modularized bioprocesses: Projects have been initiated in the area of intelligent fermentation strategies for the production of catalyst-inhibitory and labile bioproducts and in the area of integrated biotransformations (see figure) – either with advanced in situ product separation techniques or with large reaction networks for the production of complex molecules.

Integrated biotransformations: An enzyme reactor hosts a thermodynamically limited reaction – in this specific case a racemization catalyzed by an amino acid racemase that establishes a 50/50 mixture of the two enantiomers of a chiral amino acid. The reaction fluid is directed into the simulated moving bed that separates the racemate. The product stream containing the undesired enantiomer (S in this case) is concentrated and redirected into the enzyme reactor. Continuous operation guarantees a yield of 100% on starting materials, and both enantiomers are available from the same installation.

Though biocatalysts are capable of carrying out the most complex transformations of molecules, such impressive properties are frequently difficult to exploit: for example, a product that we would want to accumulate to high concentrations inhibits the biocatalyst, a desired intracellular product cannot cross the membrane, or a particularly useful enzymatic reaction is thermodynamically limited in yield. These problems severely limit the scope of products that can be obtained at present. However, they can be addressed by conceptionally very similar, forward-engineering approaches over a large range of scales: by the rational integration of modules of specific functions. This can be on reactor scale where for example a fermenter is integrated with an on-line extraction-module to remove inhibitory compounds (“integrated bioprocessing”). But the same principle can be used with multi-enzyme systems that we use in order to produce highly complex molecules that are not available from fermentations. In such multi-reaction “modules”, the ambition to rival the cell in its capacity to build complex structures needs to be accompanied by another (multi-enzyme) “module” that can – for example - provide the required energy or reducing power. This multi-scale approach defines the scope of modern bioprocessing.