Monitoring survival of phenanthrene-utilizing Sphingobium sp. P2 in soil microcosms using green fluorescent protein as a marker

Phenanthrene is a polycyclic aromatic hydrocarbon which belongs to a class of toxic environmental pollutants that has been accumulating due to a variety of anthropogenic activities. We attempted to use Sphingobium sp. P2, which is capable of utilizing phenanthrene as its sole source of carbon and energy, in bioaugmentation treatments. For successful bioremediation, monitoring the survival and metabolic activity of bioaugmented bacteria are required. This study aimed to use green fluorescent protein as a marker to estimate the survival of Sphingobium sp. P2 in bioaugmented soil microcosms. The gfp was integrated via Tn5 transposition into the chromosome of strain P2. The gfp-inserted strains were identified by green fluorescence emission under UV light. The gfp was stably maintained in strain P2, and the strain still retained the ability to use phenanthrene as a sole carbon and energy source. Soil microcosm experiments revealed that survival of the strain P2-gfp and its phenanthrene-degrading capacity may depend on indigenous microorganisms and nutrients in the soils. The strain P2-gfp can be used to evaluate the success of bioaugmentation.