The present study investigated the possibility of microbial transformations of coal to gas (biogasification) as an alternative to conventional coal mining because this approach has the potential to be less expensive, cleaner, and providing greater access to deeper coal resources. Biogasification is often associated with low rank coal such as lignite and subbituminous coal that have produced enough coalbed methane to be commercially viable in the United States and Australia. However, little work has been done to analyze the potential of biogasification in higher rank coal. For this purpose, bioassay using a wetland-derived consortium, and a coal-derived consortium were used to analyze coal samples from Pakistan belonging to different ranks (lignite to semi-anthracite). Among all samples a low volatile bituminous coal produced the maximum methane 34.95 μmol CH₄/g coal with the wetland-derived microbial consortium, followed by subbituminous coal (30.18 μmol CH₄/g coal). Lower methane levels were recorded with the coal-derived consortium with subbituminous coal, yielding the highest concentration (25.1 μmol CH₄/g coal). Methane levels appeared to be increasing on the last measurement indicating the coal-derived consortium was slower than the wetland-derived consortium but could still catalyze biogasification in higher rank coals. Quantitative polymerase chain reaction analysis for mcrA functional genes suggested that the microbial community members that produce methane (methanogens) varied during the incubations. Energy conversion efficiency of different strategies (other biological and underground coal gasification processes) was also compared and discussed. This study was the first to compare bioassay using consortia of microbes non-indigenous and indigenous to coal and indicate the potential of biogasification from many different coalbeds across Pakistan.

本研究调查了微生物向煤炭转化为天然气（生物气化）作为常规煤炭开采的替代方法的可能性，因为这种方法具有成本更低，更清洁，提供更深层次煤炭资源的更大潜力。生物气化通常与低等级煤（例如褐煤和次烟煤）有关，这些低等级煤产生了足够的煤层气，可以在美国和澳大利亚商业上使用。但是，很少有工作来分析高级煤中生物气化的潜力。为此，使用了湿地联合体和煤联合体的生物测定法分析了来自不同等级（从褐煤到半无烟煤）的巴基斯坦的煤样品。在所有样品中，低挥发性烟煤产生的甲烷量最多34。₄ / g煤与湿地微生物联合体，然后是次烟煤（30.18μmolCH ₄ / g煤）。煤衍生的财团与次烟煤的甲烷含量较低，产生的甲烷浓度最高（25.1μmolCH ₄ / g煤）。在最后一次测量中，甲烷含量似乎正在增加，这表明源自煤的财团要比源自湿地的财团慢，但仍能催化高等级煤的生物气化。mcrA的定量聚合酶链反应分析功能基因表明，在孵化过程中，产生甲烷（甲烷）的微生物群落成员各不相同。还对不同策略（其他生物和地下煤气化工艺）的能量转换效率进行了比较和讨论。这项研究是第一个比较使用非土著和土著微生物与煤炭的财团进行生物测定的方法，并指出了巴基斯坦各地不同煤层进行生物气化的潜力。