Microorganisms are capable of breaking down pollutants through metabolic processes in which the contaminants serve as sources of energy, carbon, or nutrients. This biological degradation occurs when microbes secrete enzymes that chemically alter toxic substances, converting them into simpler, less harmful compounds. For example, hydrocarbon-degrading bacteria such as Pseudomonas, Alcanivorax, and Mycobacterium can metabolize oil components by oxidizing them into carbon dioxide and water during aerobic respiration. In anaerobic conditions, certain bacteria can also use pollutants as alternative electron acceptors, allowing them to degrade compounds like nitrates, chlorinated solvents, or heavy metals. 

Fungi such as Phanerochaete chrysosporium are capable of degrading persistent organic pollutants like pesticides and dyes by producing ligninolytic enzymes that break complex molecules into smaller fragments. Some microbes even transform heavy metals into insoluble forms through redox reactions, immobilizing them in soil or sediment. Environmental factors, including pH, temperature, oxygen availability, and the presence of co-substrates, influence these processes. According to recent findings by Ghosal et al. (2016), microbial communities often function more effectively as consortia, where different species work synergistically to degrade complex mixtures of pollutants more efficiently than single strains. These biological mechanisms are central to both natural and engineered bioremediation systems, making microbes indispensable agents in the sustainable treatment of environmental contamination.