Search

Tomb Nr 1 of the ancient cemetery of Costebelle, attributed to the 4th century AD, contained the skeleton of a pregnant female and that of her foetus in the pelvic cavity. This was aged seven months, was almost complete and showed an exceptional example of bony lesions suggestive of infection. Its etiology suggested the likelihood of early congenital syphilis. This case raises the question of the theory of the importation of venereal disease into Europe, about a 1000 years later, by the crews of Christopher Columbus. The foetus of Costebelle is not an isolated example : other osteo-archaeological findings make a case for the existence of a treponeme (venereal or non venereal) in Europe before 1493.

Biosensors, sondes, and transducer elements are reviewed with respect to the application for fermentation processes of animal cells. Hereby, the possible connection of these elements to the fermentor is shown. Specially, the (possible) online determinations of the viable and total cell count, of the glucose, the lactate, the pyruvate, and the ammonia concentration in the medium of fermentors are presented. Finally, some sensors for the on-line estimation of the product concentration are described.

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.

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.