Dynamic metabolic flux analysis using B-splines to study the effects of temperature shift on CHO cell metabolism
Martínez VS., Buchsteiner M., Gray P., Nielsen LK., Quek LE.
© 2015 International Metabolic Engineering Society. Metabolic flux analysis (MFA) is widely used to estimate intracellular fluxes. Conventional MFA, however, is limited to continuous cultures and the mid-exponential growth phase of batch cultures. Dynamic MFA (DMFA) has emerged to characterize time-resolved metabolic fluxes for the entire culture period. Here, the linear DMFA approach was extended using B-spline fitting (B-DMFA) to estimate mass balanced fluxes. Smoother fits were achieved using reduced number of knots and parameters. Additionally, computation time was greatly reduced using a new heuristic algorithm for knot placement. B-DMFA revealed that Chinese hamster ovary cells shifted from 37. °C to 32. °C maintained a constant IgG volume-specific productivity, whereas the productivity for the controls peaked during mid-exponential growth phase and declined afterward. The observed 42% increase in product titer at 32. °C was explained by a prolonged cell growth with high cell viability, a larger cell volume and a more stable volume-specific productivity.