不同代谢目标下甘油代谢通量分布的模型与计算

Model and Calculation of Glycerol Metabolic Flux Distribution under Different Metabolic Targets

摘要: 胞内代谢通量的估计可为理解细胞代谢提供帮助。本研究针对肺炎克雷伯式杆菌甘油代谢，以最大化生物量和最大化ATP作为性能指标函数，以代谢通量作为决策变量，并将代谢通量平衡作为约束条件，建立数学规划模型，用以估计连续培养下不同代谢目标的代谢通量分布。数值结果表明对于给定的稀释速率和初始甘油浓度，在最大化生物量下，细胞代谢主要用于细胞生长以及生产1,3-丙二醇，且流向乙酸乙醇和流向生物质的代谢通量有显著差异；在最大化ATP下，代谢主要用于能量的生成，同时流向2,3-丁二醇和甲酸盐以及流向二氧化碳和氢气的代谢通量相差较大。

Abstract: The estimation of intracellular metabolic flux is helpful for understanding cellular metabolism. In this paper, a mathematical programming model with the metabolic fluxes as decision variables is proposed for optimizing the flux distribution of glycerol metabolic pathways in Klebsiella pneu-moniae, in which mass-balance equations are used as a constraint. In the model, we respectively use the maximization of biomass and ATP as the performance index. Numerical results show that for a given dilution and initial glycerol concentration, the substrate is mainly consumed for cell growth and the production of 1,3-proapanediol if biomass is maximized, and the metabolic flux to HAc and EtOH are significantly lower than that to the biomass. When the production of ATP is maximized, the substrate is mainly used for energy generation, while the metabolic fluxes to 2,3-butanediol and for mate, as well as to CO2 and H2 also differ greatly.