Enhanced growth of Sf-9 cells to a maximum density of 5.2x10 super(7) cells per mL and production of beta -galactosidase at high cell density by fed batch culture

Significant improvement in cell growth and protein production has been achieved in Sf-9 insect cell cultures using pulse additions of multicomponent nutrient feed concentrates. The present work focuses on investigating an alternative feeding strategy wherein the nutrients are fed in a semi continuous manner. Fed batch culture experiments were carried out to compare the two different feeding strategies, pulse and semi continuous and a process developed to achieve a cell density of 5.2x10 super(7) cells/mL of Sf-9 cells in a 3.5 L bioreactor. Production of recombinant protein beta -galactosidase was carried out by infecting the cells with baculovirus at a MOI of 10 at cell densities of 17x10 super(6) cells/mL. Specific productivity could be maintained at cell densities as high as 14x10 super(6) cells/mL. The results presented indicate that the feeding method can provide significant improvements in the performance with a reduction in the amount of total nutrients added. On-line monitoring of the culture using the capacitance probe showed that the capacitance probe can be used successfully to monitor the biomass and infection process even at higher cell densities.