Production of Choristoneura fumiferana nucleopolyhedrovirus in C. fumiferana (CF-2C1 cells) in a 3 litre bioreactor using serum-free medium

The purpose of this study, uns to develop a cell culture process in a biore actor for the production of a vir al insecticide for the spruce budworm, Ch oristoneura fumiferana. Several cell lines were tested for their growth in serum-free medium suspension cultures. One cell line, CF-124T-2C1 (CF-2C1), was successfully adapted to gr out in suspension cultures in SFM. Serum-fr ee Ex-Cell 405 medium produced a much higher cell density (6.3 x 10(6) cell s ml(-1)) than the Grace's medium supplemented with 10% fetal bovine serum (2.5 x 10(6) cells ml(-1)). Also, a higher yield of vii us was obtained in the former medium. Ex-Cell 405, was used to study the growth of CF-CI cells and the production of C. fumiferana nucleopolyhedrovirus (CfMNPV) in a 3 l bioreactor: Under these conditions, a specific growth rate (mu) of 0.027 h (-1) was obtained during the exponential growth phase, and the specific car bon dioxide evolution rate, as determined by on-line measurement, was 0.9 x 10(-16) mol cell(-1) s(-1) and 1.78 x 10(-16) mol cell(-1) s(-1) during gr owth and infection phases, respectively Mi us pi production in bioreactor c ultures infected at 1.3 x 10(6) cells ml(-1) was consistently lower than th at obtained in Erlenmeyer shake flasks. Only 26% of the cells were infected in the bioreactor compared to 44% in the shake flasks. However; a higher y ield of occluded virus was obtained in the bioreactor cultures than in shak e flasks. The production of occlusion bodies (OB) achieved in bioreactor cu ltures was 2 x 10(6) OB ml(-1).