Abstract: The invention comprises novel culture methods and devices in which biocatalysts are substantially immobilized contained, suspended and/or incubated in a chamber. At least one injection element provides a fluid flow to a perimeter of the chamber and the fluid force of the fluids flowing into the chamber works with the centripetal force created by rotation of the device to suspend the cells within the chamber, promote cell growth and/or clean the fluid as it passes thru the suspended biocatalyst. Other embodiments are also claimed and described.

Abstract: Embodiments of the present invention generally relate to novel fed-batch fermentations wherein processes of DO-stat and pH-stat are combined for nutrient feeding control.