氢分压对种间氢转移的影响

The Effect of Partial Hydrogen Pressure on Interspecies Hydrogen Transfer

在厌氧消化的产氢产乙酸阶段,从反应动力学来看,在标准生理状态下的ΔG°′均为正值,表明丙酸丁酸以及乙醇的产氢产乙酸是不能进行的。然而,在产甲烷的作用下,通过产氢产乙酸菌和产甲烷菌间的种间氢转移,体系中的氢分压大为降低,使整个消化过程得以顺利进行。文章以产氢产乙酸作用和产甲烷作用的热力学反应为基础,分别导出它们的自由能与氢分压的关系,分析了氢分压对种间氢转移的影响,得出两类菌群间种间氢转移的理论氢分压范围。进而引入细胞代谢最小能量子概念,对理论氢分压进行修正,得出沼气发酵适宜的理论氢分压范围和最佳氢分压。

Due to its △G°′〉0 under the standard physiology status, the production of hydrogen and acetic acid from butyric, propionatic and acetic acid, as well as alcohol can not occurred in the second stage of anaerobic digestion （hydrogenesis and acetogenesis stage）. However, in the presence of methanogenesis the hydrogen interspecies transfer between the hydrogenic and acetogenic bacteria and methanogenic bacteria makes partial hydrogen pressure decrease greatly, and then the whole process of anaerobic digestion can carry out favorably. This paper based upon the calculation of the thero-equilibrium for hydrogenic--acetogenic stage and methanogenic stage educes the relation between △G°′ and partial hydrogen pressure, analyses the effect of the latter on interspecies hydrogen transfer, and gets its theoretic scope. It also introduces the concept of the minimal energy units in the metabolism, revises theoretic partial hydrogen pressure, gains its suitable scope and the optimal value.