Growth kinetics of gel-immobilized yeast cells studied by on-line microscopy.

A 'microscope reactor' was used to study on-line the dynamics of gel immobilized cell systems. The applicability of the reactor is demonstrated by a study of the growth kinetics of Saccharomyces cerevisiae entrapped in 2% calcium alginate. The specific growth rates of single immobilized cells and free cells were measured. The growth of a microcolony in Ca-alginate was followed and the specific growth rate of the cells in the microcolony determined. A simple growth model was used to estimate the cell volume fraction of the yeast cells in the microcolony. As internal and external mass transfer limitations can be neglected and immobilized cell growth rates were found to be identical to those of free cells, one may conclude that immobilization does not influence cell growth under our experimental conditions.