The process of pollutant biodegradation depends mainly on the ability of microorganisms to metabolize pollutants; bacteria, fungi, and algae can degrade various contaminants such as petroleum hydrocarbons and use them as a source of energy. The microbial organisms transform the substance through metabolic or enzymatic processes. It is based on two processes: growth and cometabolism. In growth, an organic pollutant is used as sole source of carbon and energy. This process results in a complete degradation (mineralization) of organic pollutants. Microorganisms use their metabolic pathways for the biodegradation of organic pollutants into inorganic compounds, carbon dioxide, and water after their partial or complete mineralization. In anaerobic decomposition, microorganisms decompose the solid waste into biodegradable and nontoxic forms in the absence of oxygen. There are two types of bacteria which play a significant role in anaerobic decomposition reactions, which include hydrolytic bacteria and the acidogenic bacteria.

The microbial organisms transform the substance through metabolic or enzymatic processes. It is based on two processes: growth and cometabolism. In growth, an organic pollutant is used as sole source of carbon and energy. This process results in a complete degradation of organic pollutants. However, micro-organisms such as bacteria, fungi, and actinomycetes–even though they go unnoticed in your compost pile–are responsible for most of the organic material breakdown. They are chemical decomposers because they use chemicals in their bodies to break down organic matter. Microbes are used to clean up pollution treatment in processes known as 'bioremediation'. Bioremediation uses micro-organisms to reduce pollution through the biological degradation of pollutants into non-toxic substances. There are a variety of bio-decomposers such as bacteria, fungi, protozoa, etc. and they are capable to degrade cellulose by depolymerizing cellulases which hydrolyze lignocelluloses. Most commonly known bio-decomposers are fungi which include Humicola , Trichoderma , and Penicillium aspergillus. The removal or degradation of organic pollutants by the algae or “phycoremediation” is a promising bioremediation technology for decontaminating polluted sites. Phycoremediation is a sustainable and environmentally eco-friendly approach for cleaning up polluted areas. The removal or degradation of organic pollutants by the algae or “phycoremediation” is a promising bioremediation technology for decontaminating polluted sites. Phycoremediation is a sustainable and environmentally eco-friendly approach for cleaning up polluted areas. Organic matter degradation is the disintegration of mainly photosynthetically produced organic matter by microorgan- isms. It proceeds via multiple enzymatic reactions involving different microorganisms and oxidants as well as a number of intermediate compounds.