Insect cells respiratory activity in bioreactor

Abstract

Specific respiration rate ( [Formula: see text]) is a key parameter to understand cell metabolism and physiological state, providing useful information for process supervision and control. In this work, we cultivated different insect cells in a very controlled environment, being able to measure [Formula: see text]. Spodoptera frugiperda (Sf9) cells have been used through virus infection as host for foreign protein expression and bioinsecticide production. Transfected Drosophila melanogaster (S2) cells can be used to produce different proteins. The objective of this work is to investigate respiratory activity and oxygen transfer during the growth of different insect cells lines as Spodoptera frugiperda (Sf9), Drosophila melanogaster (S2) wild and transfected for the expression of GPV and EGFP. All experiments were performed in a well-controlled 1-L bioreactor, with SF900II serum free medium. Spodoptera frugiperda (Sf9) cells reached 10.7 x 10(6) cells/mL and maximum specific respiration rate ([Formula: see text]) of 7.3 x 10(-17) molO(2)/cell s. Drosophila melanogaster (S2) cells achieved 51.2 x 10(6) cells/mL and [Formula: see text] of 3.1 x 10(-18) molO(2)/cell s. S2AcGPV (expressing with rabies virus glycoprotein) reached 24.9 x 10(6) cells/mL and [Formula: see text] of 1.7 x 10(-17) molO(2)/cell s, while S2MtEGFP (expressing green fluorescent protein) achieved 15.5 x 10(6) cells/mL and [Formula: see text] = 1.9 x 10(-17) molO(2)/cell s. Relating to the Sf9, S2 cells reached higher maximum cell concentrations and lower specific respiration rate, which can be explained by its smaller size. These results presented useful information for scale-up and process control of insect cells.