Martínez Verónica S, Buchsteiner Maria, Gray Peter, Nielsen Lars K, Quek Lake-Ee
Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia.
Metab Eng Commun. 2015 Jun 19;2:46-57. doi: 10.1016/j.meteno.2015.06.001. eCollection 2015 Dec.
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.
代谢通量分析（MFA）被广泛用于估计细胞内通量。然而，传统的MFA仅限于连续培养和分批培养的指数生长中期。动态MFA（DMFA）已出现，用于表征整个培养期间的时间分辨代谢通量。在此，使用B样条拟合（B-DMFA）扩展了线性DMFA方法，以估计质量平衡通量。通过减少节点和参数的数量实现了更平滑的拟合。此外，使用一种新的节点放置启发式算法大大减少了计算时间。B-DMFA表明，从37°C转移到32°C的中国仓鼠卵巢细胞保持恒定的IgG体积比生产率，而对照的生产率在指数生长中期达到峰值，随后下降。在32°C下观察到的产物滴度增加42%，是由于细胞生长延长、细胞活力高、细胞体积大以及体积比生产率更稳定。
