The thermodynamic landscape of methanogenic PAH degradation.
The thermodynamic landscape of methanogenic PAH degradation.
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DOI：
10.1111/j.1751-7915.2009.00096.x
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发表时间：
2009-09
影响因子：
5.7
通讯作者：
Head IM
中科院分区：
文献类型：
--
作者：
Dolfing J;Xu A;Gray ND;Larter SR;Head IM
多环芳烃（PAHs）的甲烷降解一直被认为是不可能的，但在污染的近地表环境和生物降解石油储层的证据表明，这是不一定的情况。为了评估产甲烷PAH降解的热力学约束，我们已经估计了吉布斯自由能值为萘，菲，蒽，芘和christophene在水相，并使用这些值来评估几种可能的途径，使多环芳烃可能被转化为甲烷。在标准条件下（25°C，溶质浓度为1 M，气体为1 atm），这些多环芳烃的产甲烷降解产生209至331 kJ mol−1。 每摩尔甲烷产生的这是27-35 kJ mol−1，表明基于PAH的甲烷生成是放能的。 我们评估了三种潜在的PAH降解途径的能量学：氧化为H2/CO2，完全转化为乙酸盐，或不完全氧化为H2+乙酸盐。根据原位条件，PAH降解生物的能量最有利的途径是氧化为H2/CO2或转化为乙酸盐。这些不一定是环境中普遍存在的途径。这可能是因为代谢途径最佳长度的动力学理论表明，PAH降解剂可能已经朝着不完全氧化为乙酸盐加H2的方向发展，作为最佳途径。
Methanogenic degradation of polycyclic aromatic hydrocarbons (PAHs) has long been considered impossible, but evidence in contaminated near surface environments and biodegrading petroleum reservoirs suggests that this is not necessarily the case. To evaluate the thermodynamic constraints on methanogenic PAH degradation we have estimated the Gibbs free energy values for naphthalene, phenanthrene, anthracene, pyrene and chrysene in the aqueous phase, and used these values to evaluate several possible routes whereby PAHs may be converted to methane. Under standard conditions (25°C, solutes at 1 M concentrations, and gases at 1 atm), methanogenic degradation of these PAHs yields between 209 and 331 kJ mol−1. Per mole of methane produced this is 27–35 kJ mol−1, indicating that PAH‐based methanogenesis is exergonic. We evaluated the energetics of three potential PAH degradation routes: oxidation to H2/CO2, complete conversion to acetate, or incomplete oxidation to H2 plus acetate. Depending on the in situ conditions the energetically most favourable pathway for the PAH‐degrading organisms is oxidation to H2/CO2 or conversion into acetate. These are not necessarily the pathways that prevail in the environment. This may be because the kinetic theory of optimal length of metabolic pathways suggests that PAH degraders may have evolved towards incomplete oxidation to acetate plus H2 as the optimal pathway.
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影响因子：
11.4
作者：
DOLFING, J;HARRISON, BK
通讯作者：
HARRISON, BK
影响因子：
2.7
作者：
Chang, W;Um, Y;Holoman, TRP
通讯作者：
Holoman, TRP
影响因子：
11.4
作者：
Sverdrup, LE;Nielsen, T;Krogh, PH
通讯作者：
Krogh, PH
影响因子：
64.8
作者：
Jones, D. M.;Head, I. M.;Larter, S. R.
通讯作者：
Larter, S. R.
影响因子：
11
作者：
Dolfing, Jan;Larter, Stephen R.;Head, Ian M.
通讯作者：
Head, Ian M.