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A new encapsulation method was developed for the cultivation of mammalian cells. The capsules were produced using a solution of sodium cellulose sulphate (CS)(1.5%) and poly-dimethyl-diallyl-ammonium chloride (PDMDAAC). When CS droplets fell into the precipitation bath consisting of a 2% solution of PDMDAAC, immediately a membrane at the interphase was built up. The influences of varying encapsulation process parameters on capsule characteristics, cell growth, and monoclonal antibody production were tested. This new method showed advantages when compared to other methods mainly due to time simplicity of the whole process.

Mass culture of immobilized cells in airlift-fermenters usually ends up with the beads accumulating in the foamy layer on the surface of the reactor fluid or, in stirred tankreactors, with partial destruction of the beads. We tried to use an airlift fermenter vessel for growing cells, immobilized in agarose beads. Instead of using the gas for driving, we mounted a slowly turning marine type impeller within the drought tube. Oxygen was supplied on occasional demands by the original sparger. This set up leads to sufficient operational characteristics of the reactor without accumulation of the beads in the foamy layer and without mechanical destruction. Different productivities of either immobilized cells or cells in free suspension culture are reported.

A new and simple device for the on-line determination of the total cell count in fermentation vessels is presented. It is based on fibre optic techniques, produces a constant infrared signal and determines the cell count via the scattered light. The linear range between the cell count and the infrared response lies between 1 X 10(5) and more than 2 X 10(6) cells per ml. This sensor shows good correlation between the cell count and the infrared response in fermentations with cell viability of more than 80%. The feeding pumps in these fermentations can be controlled via this sensor to get fermentation with stationary cell counts.