Microbe–mineral interactions are very pervasive in nature. Since coal is a chief source of nonrenewable energy and finds its application in a wide variety of sectors, the importance of microbe–mineral interaction is indispensible for developing a sustainable microbial coal biotechnology. The underlying necessity of microbe–mineral interaction is also linked with acid mine drainage that is a universal environmental problem in iron- and sulfur-rich environments. In the view of the fact that microbes act as a storehouse of several novel biomolecules or enzymes, they can be used for bioprocessing on an industrial scale incorporating innovative ideas and advanced technologies. The coal mines comprise of several synergistic interactions occurring between microbes and minerals which vary according to pH, temperature, mineralogy, and metal concentration, ultimately forming a viable microbial community.

Certain specific groups of microbes associate symbiotically with each other in order to fulfill their nutritional requirements and endure their growth and survival. Bacterial species belonging to the group α-, β-, γ-, and δ-proteobacteria have been found to predominate in the coal mine areas, while certain other bacterial lines of descent fall under the division Nitrospira, Firmicutes, and Acidobacteria. Similarly, archeal families comprising of Thermoplasmatales and Sulfolobales have been reported from the acid mine drainages. However, few reports have additionally focused on the existence of eukaryotes in these sites. Majority of these microbial species employ essential enzymes required for various key transformations occurring in an acid mine drainage. Certain autotrophic groups are capable of oxidizing or reducing iron or sulfur to obtain their sole source of energy, whereas certain other heterotrophic groups are adept in utilizing organic compounds for their sustenance. Thus, most of the subsurface interactions occurring in the environment proceed through iron or sulfur oxidation, organic carbon oxidation, fixation of carbon or nitrogen, extracellular polymeric slime production, as well as iron and sulfur reduction. This review highlights the necessary interactions occurring between microbes and minerals, which would further assist in understanding the innate mechanism behind various crucial processes occurring in nature. Moreover, this understanding of the inherent mechanisms responsible in the microbe–mineral interactions would lead to the development of an efficient and eco-friendly technology toward the judicious use of natural resources and pave way towards a sustainable microbial coal technology.