Abstract: The horizontal transfer of mobile genetic elements (MGEs) in environmental microbial communities plays an important role in the evolution of bacterial genomes and the adaption of microbial populations to specific environmental stress. Inoculation of the bacterial strains with MGEs with pollutant-degrading gene and the subsequent horizontal transfer of the MGEs to one or various well-established and competitive indigenous bacterial populations in an ecosystem will allow the catabolic gene to be transferred and expressed in indigenous microbial populations, and hence, the survival of the introduced donor strains is no longer needed to be considered. The MGE-mediated bioremediation provides the feasibility for developing new bioremediation strategies. This paper summarized the diversity of MGEs with pollutant-degrading gene in the environment and the important roles of these MGEs in promoting pollutant degradation, introduced the methodological approaches for the isolation of the MGEs from environmental samples , and listed several studies that monitored the horizontal transfer of the MGEs in polluted soil, activated sludge, and other bioreactors.

Key words: mobile genetic elements (MGEs), horizontal gene transfer (HGT), exogenous isolation, bioremediation