Optimizing amino acid composition of CHO cell culture media for a fusion protein production

The amino acid composition of CHO cell culture media for manufacturing an antibody fusion protein (B1) was optimized using data obtained through metabolic flux analysis. The metabolic flux analysis was performed using the metabolic rates derived from two semi-steady states of continuous culture. The amino acid composition was the same for media used in both the fed-batch and continuous cultures, which made the modification of amino acid composition suggested by the metabolic flux analysis applicable to the fed-batch culture. The flux analysis indicated that methionine, tryptophan, asparagine and serine were limiting, while alanine, arginine, glutamine and glycine were in excess at the semi-steady states. Based on this result, the limiting amino acids were increased while those in excess were reduced to obtain balanced amino acid composition in both the batch and feed media. The fed-batch cell cultures using the modified media generated less lactate and ammonia, and more significantly, increased peak cell densities by 55% and B1 protein titer by 27% without any impact on final sialic acid content, a quality attribute of the B1 protein.