Syntrophic interaction in organochlorine bioremediation: A review

Organochlorine compounds are released in the environment by many sources such as industrial pollution, naturally in marine sponge’s metabolism or agricultural application (pesticides). These compounds can have carcinogenic and lethal effects on human health through an ability to concentrate in biota and magnify in the food chain. In recent years, interest in the microbial biodegradation of pollutants has intensified as effective applications to find sustainable ways to clean up contaminated environments. Enhancing the growth of microbes might already be living at the contaminated site and to add specialized microbes have ability to degrade the contaminants become a common technique known as bioremediation. Understanding how microbial communities metabolize and respond to contaminants is the key to predicting contaminant fate at contaminated sites in bioremediation. The organohalide respiration process under anaerobic conditions involves a consortium of many microorganisms working together with complex relationships known as syntrophy. Syntrophic relationships, such as those observed between fermentative bacteria and methanogens, is an obligate form of mutualism in which both partners are dependent on each other. Syntrophic interactions are a unique niche in nature and play an important role in carbon cycling under anoxic conditions. Associations of syntrophic fermentative organisms and partners that consume fermentation products contribute to the anaerobic biodegradation of organochlorines. Addition of substrates that ferment to H2 to stimulate reductive dechlorination have been demonstrated to be effective in bioremediation applications. However, due to changes in community structure and difficulties in studying the function of individual populations in defined culture, our understanding of syntrophic interactions is still limited.