Microbial bioremediation of soils contaminated with petroleum hydrocarbons

Abstract

Microbial bioremediation is an eco-friendly and sustainable solution to the urgent challenge of environmental pollution. Microbial biodegradation and transformation of pollutants, such as heavy metals, hydrocarbons, oils, pesticides, and dyes, occur mainly through enzymatic processes. This method of microbial transformation is more convenient and preferable than direct chemical or physical treatment. By utilizing living microorganisms such as bacteria, fungi, and algae, hazardous pollutants found in the environment can be detoxified and degraded into by-products that are less toxic than the original compounds. Microorganisms can be found naturally at a contaminated site or they can be intentionally introduced from outside for bioremediation purposes. These microorganisms are capable of breaking down and transforming pollutants through their metabolic processes, using them as a source of nutrition. The degradation of pollutants usually requires the cooperation of multiple types of microbes, so in some cases, adding specific microbes to the contaminated site can accelerate the degradation process. The process of biodegradation relies upon a suitable environment, the type and solubility of the pollutant, and the pollutant’s bioavailability to microbes. Environmental conditions are therefore controlled or modified to allow for sufficient microbial growth, resulting in efficient biodegradation. Recent studies have highlighted the use of genetically modified microorganisms and techniques for bioremediation purposes. This review provides an overview of the different strategies used in microbial bioremediation, their benefits and drawbacks, as well as the main principles and types of contaminants bioremediation methods.