Evaluation of monitoring approaches and effects of culture conditions on recombinant protein production in baculovirus-infected insect cells.

The baculovirus infection process of Spodoptera frugiperda (Sf9) insect cells in oxygen-controlled bioreactors in serum-free medium was investigated using a recombinant Autographa californica (AcNPV) virus expressing beta-galactosidase enzyme as a model system. A variety of monitoring techniques including trypan blue exclusion, fluorescent dye staining, oxygen uptake rate (OUR) measurements, and glucose consumption were applied to infected cells to determine the best way of evaluating cell integrity and assessing the course of baculovirus infection. The metabolism of newly-infected cells increased 90% during the first 24 hours, but as infection proceeded, and cells gradually succumbed to the baculovirus infection, the cytopathic effect of the baculovirus on the cells became evident.

Optimization of batch fermentor sterilization.

This article presents a calculation procedure useful for the optimization and scale up of batch sterilization cycles in large-scale fermentors. This technique determines the sterilization temperature and hold-time necessary to minimize nutrient damage in a specific fermentor. The method can also be used for "scaledown" experiments to eliminate sterilization conditions as a scale up parameter.