Mass deposits of fossil coals can be formed in certain evolution periods of the Earth’s biosphere, and they are the result of biogeocenosis functioning. A unique combination of ecological factors leads to the emergence of specific biomes with short trophic chains, an imbalance in the carbon cycle and desynchronization in the flows of substance and energy. The molecular structure of coal is a complex conglomerate of various stable organic compounds of primary and secondary metabolites of biogeocenosis reducers. The molecular profile includes numerous classes of lowand high-molecular organic substances that interact closely with each other. Multiple classes are not endless, the interaction is not chaotic, and their number and relationships are determined by paleoecologic patterns and coalification. Even a small fragment of the profile includes valuable information about the genesis of individual compounds and the biogeochemical situation when forming the coal bed. Microbiota impact does not end with a period of mortmass accumulation, which is never fully mineralized. In the coalification process, favorable environmental conditions may arise for the rebirth of the microorganisms’ lives in coal beds.