An essential but missing component in our understanding of microbial interactions leading to coal bed methane (CBM) formation lies in the relationship between coal and coal-adhering microorganisms. Here, we explored the influence of surface physico-chemistry on the microbial cell attachment on coal, utilising a known coal-oxidising bacterium P. fluorescens Pf-5 as a model. Based on the interfacial free energy of adhesion calculation and direct observation of cell adhesion on coal, natural lignite and subbituminous coals offered the most conducive surface for cell attachment driven by favourable hydrophobic and acid-base interactions. Coal pretreatments dramatically decreased coal surface hydrophobicity and increased its electron-donating potential (γ ⁻), resulting in unfavourable interaction with cells that were hydrophilic and possessed high γ ⁻. An exception to this was peroxide treatment, which maintained a low γ ⁻ of the coal surface and allowed favourable coal-cell interaction to occur. Cell colonisation on lignite appeared to be the strongest amongst all coal types, likely due to the relatively high van der Waals surface energy component that influence the adhesion strength in favourable cell-coal interactions. This would partly explain the higher methanogenic potential found in lignite compared to subbituminous coal in previous studies, as more adsorbed cells potentially lead to greater liberation of small organic compounds. Although our cell enumeration results generally correlated with the thermodynamic data, some exceptions were present that signify the biological role in cell-to-coal attachment and biofilm formation. Overall, these findings provide insights into the fundamental parameters that are involved in cell-coal adhesion dynamics at the molecular level.

在我们对导致煤层气（CBM）形成的微生物相互作用的理解中，一个必不可少的要素就是煤与粘附煤的微生物之间的关系。在这里，我们利用已知的煤氧化细菌萤光假单胞菌Pf-5作为模型，探索了表面物理化学对煤上微生物细胞附着的影响。基于粘附力的界面自由能计算和直接观察细胞在煤上的粘附力，天然褐煤和次烟煤为疏水性和酸碱相互作用的驱动提供了最有利于细胞粘附的表面。煤的预处理显着降低煤表面的疏水性和增加了它的供电子电势（γ ^-），导致不利的相互作用与该是亲水的且具高细胞γ ^- 。一个例外是过氧化处理，这保持了低的γ ^-煤表面的表面，并允许发生良好的煤细胞相互作用。在所有类型的煤中，褐煤上的细胞定殖似乎是最强的，这可能是由于相对较高的范德华表面能组分影响了良好的煤-煤相互作用中的粘附强度。与以前的研究相比，这可以部分解释褐煤与次烟煤相比具有更高的产甲烷潜力，因为更多的吸附细胞可能导致小有机化合物的更大释放。尽管我们的细胞枚举结果通常与热力学数据相关，但仍存在一些例外情况，这些例外情况表明了细胞与煤的附着和生物膜形成中的生物学作用。总体，