This Small Business Innovation Research (SBIR) Phase I project proposes to examine the biochemical and metabolic characteristics of a novel Centrifugal Bioreactor (CBR) used to culture suspension mammalian cells. The CBR achieves suspension of animal cells at densities greater than 10 8 cells/mL in a fluidized bed where nutrient liquid flow forces counteract centrifugal forces. The phase I overall goal is to provide a solid scientific understanding of the CBR culture process. The specific technical objectives include measuring the growth rate of a representative cell line in the CBR , establishing steady-state operation of the CBR in terms of nutrient consumption and metabolite production by the cells and manipulating the steady state by changing the dissolved oxygen concentration at the CBR inlet.<br/><br/>The commercial application of this project will be in the area of animal cell culture bioreactors. The principal impact of the proposed technology will be to reduce the scale and capital costs of commercial animal cell culture equipment and to potentially improve the quality and consistency of secreted protein product.