Aerobic and Anaerobic Biodegradation

This document provides an in‐depth explanation, detailing the processes of aerobic andanaerobic biodegradation. It is intended for general audiences and will provide the reader withthe necessary information to understand what is happening during the biodegradation process.For those interested in the biochemical processes of the microbial organisms this document willprovide a high level explanation of the aerobic and anaerobic processes.BiodegradationBiodegradation is the process by which organic substances are broken down into smallercompounds by the enzymes produced by living microbial organisms.

The microbial organismstransform the substance through metabolic or enzymatic processes. Biodegradation processesvary greatly, but frequently the final product of the degradation is carbon dioxide or methane.Organic material can be degradedaerobically, with oxygen, oranaerobically, without oxygen.Biodegradable matter is generally organic material such as plant and animal matter and othersubstances originating from living organisms, or artificial materials that are similar enough toplant and animal matter to be put to use by microorganisms. Some microorganisms have theastonishing, naturally occurring, microbial catabolic diversity to degrade, transform oraccumulate a huge range of compounds including hydrocarbons (e.g. oil), polychlorinatedbiphenyls (PCBs), polyaromatic hydrocarbons (PAHs), pharmaceutical substances,radionuclidesand metals.Aerobic BiodegradationAerobic biodegradationis the breakdown of organic contaminants by microorganisms whenoxygen is present. More specifically, it refers to occurring or living only in the presence ofoxygen; therefore, the chemistry of the system, environment, or organism is characterized byoxidative conditions.

Many organic contaminants are rapidly degraded under aerobicconditions by aerobic bacteria called aerobes.Aerobic bacteria (aerobe) have an oxygen based metabolism. Aerobes, in a process known ascellular respiration, use oxygen to oxidize substrates (for example sugars and fats) in order toobtain energy.Before cellular respiration begins, glucose molecules are broken down into two smallermolecules. This happens in the cytoplasm of the aerobes. The smaller molecules then enter amitochondrion, where aerobic respiration takes place. Oxygen is used in the chemical reactionsthat br