Enhanced growth of sf-9 cells to a maximum density of 5.2 × 107 cells per mL and production of β-galactosidase at high cell density by fed batch culture

Abstract

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 (Bédard et al., 1994; Chan et al., 1998). 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 5.2 × 107 cells/mL of Sf‐9 cells in a 3.5 L bioreactor. Production of recombinant protein β‐galactosidase was carried out by infecting the cells with baculovirus at a MOI of 10 at cell densities of 17 × 106cells/mL. Specific productivity could be maintained at cell densities as high as 14 × 106 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. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 68: 381–388, 2000.

Multifrequency permittivity measurements enable on‐line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells

“…The successful application of this technology in a wide variety of cell culture processes is described in the literature. 5,6,9,[13][14][15][16] Several studies report measurements of the permittivity at one single or two frequencies (to reduce the effect of a changing media composition on the signal). Permittivity measurements are described as a tool to directly measure the viable biomass.…”

Growth, metabolism and baculovirus production in suspension cultures of an Anticarsia gemmatalis cell line

“…Moreover, the metabolic characteristics of a cell line can determine the selection of a particular cultivation strategy, such as batch, fed-batch or perfusion. As an example, the lack of production of toxic by-products in well-oxygenated cultures of the lepidopteran insect cell lines IPLB-Sf-21 and Sf9 makes it possible to use nutrient feeding strategies in order to keep cultures in production at very high cell densities (Nguyen et al 1993;Bé dard et al 1997;Elias et al 2000). On the contrary, Tn-5 and High-Five cell lines display a metabolic behavior characterized by the accumulation of lactate and ammonia (Rhiel et al 1997) that could limit the applicability of nutrient feeding strategies in high density cultures of these cell lines (Ikonomou et al 2003).…”

On-line monitoring of responses to nutrient feed additions by multi-frequency permittivity measurements in fed-batch cultivations of CHO cells

“…However, with current sensor technology, on-line monitoring of the physiological state remains a challenging task, rendering its use as a bioprocess control parameter complex (Konstantinov 1996;Henry et al 2007). Permittivity-based in situ probes are now an established tool for the measurement of biomass in real-time in a wide variety of cell culture processes (Kamen et al 1996;Zeiser et al 1999;Elias et al 2000;Zeiser et al 2000;Ducommun et al 2001Ducommun et al , 2002Cannizzaro et al 2003). Permittivity is a direct measure of the membrane enclosed volume fraction or biovolume of the cell suspension.…”