ABSTRACT
Membrane technology has been applied in many different areas of biotechnology. This chapter focuses on the use of membranes for cell recycling in fermentation processes. The different modes of operating membrane reactors: external membrane loop, internal membrane, and immobilization in hollow-fiber unit. Complete cell recycling for improving the cell density may be especially attractive when dealing with product-inhibited as well as substrate-inhibited cell cultures. The technique of complete cell recycling has been suggested as a method for determining the maintenance coefficient. Membrane recycling cultivation offers an interesting new way to operate with high cell densities, to efficiently reduce inhibitory compounds, and to administer toxic substrates to growing cells. The changes observed in both intracellular protein pattern and product composition from the cells must be further evaluated before the full potential of this technology can be utilized.
