Alteration of glucose consumption kinetics with progression of baculovirusinfection in Spodoptera frugiperda cells

We have used the initial-rate approach to characterize changes in the gluco se consumption kinetics of baculiovirus-infected Spodoptera frugiperda clon e 9 (Sf9) cells with the progression of the infection process. The specific glucose consumption rate (q(G)) of cultured baculovirus-infected Sf9 cells was measured at 4, 8, 12, 16, and 24 h postinfection (h.p.i.) in media con taining 4-35 mM glucose. Higher medium glucose concentrations resulted in h igher final extracellular virus and recombinant beta-galactosidase yields. q(G) was related to the extracellular glucose concentration by means of a M ichaelis-Menten relationship. The apparent Michaelis-Menten constant (K-m) for glucose consumption was found not to change significantly during the pr ogression of the infection process, and remained between 6.2 and 7.2 mM. Ho wever, the maximal specific glucose consumption rate (q(Gmax)) was found to rapidly increase after infection, peaking at 16 h.p.i. at a value four tim es that for uninfected Sf9 cells. The kinetic analysis of glucose consumpti on rates in baculovirus-infected Sf9 cells presented here will aid in the o ptimal design and operation of bioreactor systems for the large-scale produ ction of recombinant products from the bacullovirus/insect cell system.