Measuring growth of a phenanthrene-degrading bacterial inoculum in soil with a quantitative competitive polymerase chain reaction method

We measured growth of a phenanthrene-degrading bacterium, Arthrobacter, strain RP17, in Forbes soil, amended with 500 μg g^-1 phenanthrene using a quantitative competitive polymerase chain reaction method. The inoculum, which was not indigenous to Forbes soil, grew from 5.55x10⁵ colony forming units (cfu) g^-1 to 1.97x10⁷ cfu g^-1 within 100 h after the cells were added to the soil. Maximum population density was reached before the highest degradation rate was observed 150 h after the cells were added to soil. Population density remained stable even after 56% of the phenanthrene had mineralized. This study is one of the few documented examples of growth by a non-indigenous bacterium in a non-sterile soil amended with a pollutant. Copyright (C) 2000 Federation of European Microbiological Societies.