低阶煤微生物厌氧降解增产甲烷的真菌与产甲烷菌协同作用机理

Microbially enhanced coalbed methane (MECoM) can not only increase coalbed methane (CBM) reserves, but also improve the permeability of coal seam, thus enhancing CBM recovery. Currently, the essential and mechanism of MECoM, that methane are produced by anaerobically biodegrading coal, is studied mostly by bacterial analysis. However, fungi have a natural advantage in the degradation of complex organic compounds and our previous study found fungi in produced water from Qinshui Basin could anaerobically degrade anthracite and syntrophically produce methane with methanogens. Thus, lignite which can be more easily utilized by microbe will be used here to cultivate fungal flora from produced water. The metabolic pathway of enhancing methane by synergetically and anaerobically degrading coal using fungi and methanogens will be studied though the aspect of microbe, enzyme, intermediates, and coal, at such different scales and dispersions as pulverized coal in bottles, lump coal in fermentation tank, and raw coal in physical simulation device. And the effect on raw coal by synergetically and anaerobically degrading coal using fungi and methanogens will be analyzed in physical simulation device which will be characterized by pore and fraction, permeability, and gas adsorption/desorption. Then, the mechanism of synergistic effects between fungi and methanogens on methane enhancement by anaerobically biodegrading low rank coal will be illuminated based on the results of metabolic pathway and effect on raw coal. These results will lay a foundation for understanding the mechanisms of anaerobically biodegrading coal to produce methane in coal seams, and provide basis to accelerate methane production by coal biodegradation.

微生物增产煤层气能够增加煤层气储量，改善储层物性，提高煤层气采收率。其核心机理是微生物厌氧降解煤产甲烷。目前研究主要以细菌角度开展，而真菌在复杂有机物的降解中具有天然优势，且项目组前期研究发现沁水盆地产出水中真菌能够与产甲烷菌协同降解煤产甲烷。由此，项目拟以微生物更易利用的褐煤为研究对象，从产出水中培育厌氧降解煤的高效真菌菌群，分析培养条件对菌群厌氧降解煤的影响机制。在厌氧瓶粉煤、发酵罐块煤、模拟装置试件等不同尺度和煤松散度下，从微生物、生物酶、中间产物、煤结构四个方面分析真菌和产甲烷菌协同厌氧降解煤增产甲烷的代谢途径；在模拟装置试件尺度下，以孔裂隙、渗透率、气体吸附/解吸等煤体特性表征真菌与产甲烷菌协同厌氧降解对煤体的作用，从而从代谢途径和煤体作用两方面阐明低阶煤微生物厌氧降解增产甲烷的真菌和产甲烷菌协同作用机理，为理解微生物厌氧降解煤产甲烷机理奠定基础，为提速生物降解煤产甲烷提供依据。

微生物增产煤层气的核心机理是微生物降解煤产甲烷。功能微生物是该过程的主要实施者，也是决定产甲烷效率的主要因素之一。基于真菌在难降解化合物，尤其是芳香类化合物的降解中的天然优势，项目从煤层气田产出水中富集获得了降解煤产甲烷的真菌-产甲烷菌混合菌群和降解芳香化合物的真菌功能菌群，分析了培养条件对甲烷生成的影响；建立了混合菌群和功能菌群的配伍体系，实现了菌群结构调控、甲烷产量提升，证明复配是一种有效的甲烷增产方法。在粉煤和块煤水平探讨了混合菌群和复配菌群的降解煤产甲烷机理以及反应尺度对甲烷生成的影响。建立了煤层生物产甲烷的物理模拟装置，在实验室水平初步分析了生物降解对煤储层的影响。研究结果为进一步阐明微生物厌氧降解煤产甲烷机理、提高甲烷产量奠定基础。