Fed-batch culture of insect cells with exponential feeding of amino acid and yeastolate solution

Abstract

Amino acids rather than sugars are the primary limiting substrates for the culture of insect cells in a Grace's medium. When cultures are supplemented with amino acids, the yeastolate components other than the amino acids become the secondary limiting substrates. For the fed-batch culture of insect cells, a solution containing concentrated amino acids and yeastolate was supplied using an exponential feed¯ow rate calculated from mass balance equations. During the batch period the speci®c growth rate was 0.02 h )1 , whereas during the fed-batch period it was measured as 0.007 and 0.012 h )1 on the basis of the cell numbers and the dry cell weight, respectively. This difference in the speci®c growth rates in the fed-batch period is caused by an increase in the cell size during this period. Furthermore, in fed-batch cultures, dissolved oxygen was found to be a limiting factor for high cell-density cultures.