Biocatalysis is moving from an enabling tool towards a lowest cost and resource-saving approach for the production of chemicals. The research group's endeavor is to transfer the widely acknowledged potential of biocatalysis into commercial applications. One focus of our group is to design and apply whole-cell biocatalysts (-cell factories) that can perform multi-step reactions in a single cell and one reactor. This concept has an enormous commercial potential: Complex processes requiring multiple steps often performed under different conditions (temperature, pressure, pH) can be substituted by very simple and cheaper single pot processes. Another benefit is that expensive enzyme purification of the different enzymes often limiting commercial applications is no longer required and the biocatalyst can be produced in a single instead of multiple fermentations. In order to rationally design and optimize these biocatalysts bottlenecks in the newly formed pathway have to be identified by simulating the coupled reactions including mass transfer through cell membranes based on a computer model. Identification of kinetic parameters and the bottlenecks will then be used to target specific enzymes properties (selectivity. stability. activity) for optimization by directed evolution and genetic engineering means (adaptation of expression levels). Important to the success will be an interdisciplinary teamwork of scientists for which the project house offers an excellent supportive framework.