Single-use bioreactors are usually applied in the biopharmaceutical industry for mammalian cell culture processes. For microbial processes, concepts like the CELL-tainer® technology allow comparable gas-liquid mass transfer rates like in stirred tank reactors. In the CELL-tainer, the rocking motion of the bag is generated with a combination of a vertical and horizontal movement. Due to a 2-D rocking motion, the turbulence in the liquid is intensified. Thus, volumetric oxygen transfer rates (kLa) of over 400 h-1 could be achieved. Recently, the successful scale-up of an Escherichia coli nutrient-limited fed-batch cultivation from the 15 L to the 150 L scale in the CELL-tainer single-use bioreactor has been conducted. A final biomass concentration of 45 gL-1 within 24 hrs was obtained in cultivations proving the general suitability of this reactor concept for the application of bacterial processes. The combination of intelligent software sensor control strategies and currently improving (single-use) sensors will lead to a reduction of current drawbacks and improve control of bacterial fed-batch processes. The availability of single-use bioreactors for microbial cultivations widens their potential, not only in biopharmaceutical processing, but also as a pre-culture bioreactor for large scale processes and as a suitable tool in bioprocess development.