In the pharmaceutical industry mammalian cell lines are the primary expression system in the production of therapeutic recombinant proteins. Despite its diverse drawbacks, the stirred tank reactor serves here as major workhorse for most applications. To overcome the limitations faced, improved bioreactors are needed to provide a more favorable in vitro environment to mimic in vivo conditions. In order to establish a suitable culture system, the cell's responsiveness to environmental stress is evaluated to identify and anticipate the impact of this process parameter during cell cultivation. Based on these studies, a novel bioreactor featuring good mass transfer characteristics at low shear values both in maximal magnitude as well as distribution is constructed. Its unique cultivation microenvironment enhances cell growth and protein production and makes it superior to conventional stirred tank reactors. Especially nowadays in the environment of a fast growing and competitive market, governmental price control and rising quality requirements, the proposed bioreactor provides a suitable tool for biopharmaceutical research, development, and production.