Cell immobilization

We will be concerned in this chapter with methods that may be used to immobilize live rather than dead cells. The use of immobilized viable cells is seen as an alternative approach to extracellular metabolite production by traditional fermentation technology. There are a number of reasons why this may be advantageous. First, immobilized cells are easily utilized in continuous flow reactors without, theoretically, the contamination of the product stream by cellular material. Second, cell densities in the reactor of at least one order of magnitude greater than with traditional fermentation techniques are possible. Third, immobilization has been reported to enhance the longevity of cells, in particular plant cells, which is therefore useful in extending the productive life of slow-growing cells. Fourth, it has been suggested that immobilization may enhance the release of secondary metabolites from cells, particularly when (as in plant cells) these metabolites are normally stored intracellularly.