厌氧消化的胞内代谢通量与关键节点特征分析

Anaerobic Digestion of Intracellular Metabolic Fluxes and Key Node Characteristics

文章依据厌氧消化1号模型建立便于实施代谢通量分析的代谢网络,以pH为扰动因子,研究不同pH值下厌氧消化(AD)过程中各代谢途径通量的分布信息,明确了AD胞内代谢的主要途径和关键节点的刚柔性。结果显示,糖代谢阶段经过EMP途径的6-磷酸葡萄糖通量约为95.14%,表明EMP途径在AD糖代谢中占主导。在丙酮酸代谢过程中,主要的代谢途径为86.53%的丙酮酸代谢为乙酰CoA,再由54.66%的乙酰CoA代谢为乙酸。在产甲烷阶段,66.63%的甲烷来源于乙酸,其余由氢还原CO_(2)形成,乙酸转换为AD主要的产甲烷途径。同时根据不同pH条件下,关键节点上通量分配比的变化特征可知,6-磷酸葡萄糖、乙酰CoA和乙酸为AD过程中的柔性节点,丙酮酸为刚性节点,可以针对柔性节点实施调控,以达到提高AD处理效率的目的。

A metabolic network that facilitates metabolic flux analysis was established according to Anaerobic Digestion Model l,and pH was used as the disturbance factor to study the distribution information of the fluxes of each metabolic pathway in anaerobic digestion(AD)at different pH values,and the rigidity flexibility of the main pathways and key nodes of AD intracellular metabolism was clarified.The results showed that the glucose 6-phosphate flux through the EMP pathway in the glucose metabolism stage was about 95.14%,indicating that the EMP pathway dominates AD glucose metabolism.In the process of pyruvate metabolism,the main metabolic pathway was 86.53%pyruvate metabolized to acetyl CoA,which was then metabolized by 54.66%acetyl CoA to acetic acid.In the methane-producing stage,66.63%of the methane was derived from acetic acid,the rest was formed by hydrogen reduction CO_(2),and acetic acid was converted to AD,the main methane-producing pathway.At the same time,according to different pH conditions,the change characteristics of the flux allocation ratio on the key nodes can be seen that glucose 6-phosphate,acetyl CoA and acetic acid are the flexible nodes in the AD process,and pyruvate is the rigid node,which can be regulated for the flexible nodes to achieve the purpose of improving the efficiency of AD processing.