Metabolic flux analysis during galactose and lactate co-consumption reveals enhanced energy metabolism in continuous CHO cell cultures

Chinese Hamster Ovary (CHO) cells are the main expression system for production of therapeutic recombinant (r-) proteins. The increased demand for these therapeutics has boosted the development of more robust production processes. Use of optimised feed/media has dramatically improved the performance of CHO cells in culture. However, such progress in biomass synthesis and r-protein production often come with an increased accumulation of lactate. In this study, we present a combined feeding strategy that uses galactose and lactate to replace glucose in CHO cell cultures. Replacement of glucose by galactose and lactate sustained cell growth and r-protein production in CHO cells. This strategy supported a better-balanced and more efficient metabolism, observed by an overall decreased consumption of carbon sources and amino acids, associated with an increased ATP production per C-mol consumed. Our results provide new insights of CHO cell metabolism in glucose-free media based on galactose and lactate.