Calcium Alginate Film Formed on a Stainless Steel Mesh

Viable cells can be immobilized in calcium alginate to improve the volumetric productivity of the fermentation process by increasing the cell numbers per unit of bioreactor volume and using the cells in their most productive growth phase. Also, in a continuous process, immobilization prevents cells from washing out of the bioreactor with the fermentation product. Hence, the feed rate of fresh substrate medium per unit of bioreactor volume (i.e., the dilution rate) is uncoupled from the growth rate of the cells. This is not the case for a continuous, freely suspended cell bioreactor in which the product withdrawal rate must be carefully balanced with the cell growth rate to avoid washout.