Semi-continuous production with the baculovirus expression system.

Summary s-galactosidase was produced in a two-stage reactor system. In the first reactor of this system Spodoptera frugiperda Sf-21 cells were cultured. In the second reactor the cells were infected with a recombinant baculovirus containing the lacZ gene from Escherichia coli . The infection reactor was inoculated with part of the reactor contents of the previous run. With this system 12 successive runs were possible before the production of s-galactosidase (about 20 U per ml) decreased.