Role of Microorganisms in the Degradation of Organic Pollutants: A Review

摘要

Environmental pollution by organic waste especially hydrocarbons, pesticides, herbicides and other toxic wastes is a global problem. The petroleum industry has created economic boom for many countries and at the same time led to environmental and socio-economic problems. Release of hydrocarbons into the environment whether accidental or due to human activities is the main cause of water and soil pollution. Pesticide application on agricultural soil is now a common practice. Some of these pesticides persist in the soil to form pollutants which may occasionally lead to surface and ground water contamination. It is an important subject to study the role of microorganisms in organic pollutant biodegradation as it is a safe alternative to physicochemical techniques. This paper summarized the general principles of organic pollutant degradation by microorganisms. Emphasis was laid on the biochemistry of hydrocarbon oxidation viz; terminal and sub terminal oxidation of n-alkanes as well as anaerobic degradation of alkanes. This paper also highlighted the pathways for the biodegradation of organic chemicals such as pesticides as well as factors affecting organic pollutant biodegradation. Beside these factors affecting biodegradation, efforts at improving the biodegradative capabilities of microorganisms through biostimulation, bioaugmentation and the use of genetically engineered microorganisms (GEM) were also discussed.