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, str ain RP17: in Forbes soil, amended with 500 mug g(-1) phenanthrene using a q uantitative competitive polymerase chain reaction method. The inoculum, whi ch was not indigenous to Forbes soil, grew from 5.55 x 10(5) colony forming units (cfu) g(-1) to 1.97 x 10(7) cfu g(-1) within 100 h after the cells w ere added to the soil. Maximum population density was reached before the hi ghest degradation rate was observed 150 h after the cells were added to soi l. Population density remained stable even after 56% of the phenanthrene ha d mineralized. This study is one of the few documented examples of growth b y a nonindigenous bacterium in a non-sterile soil amended with a pollutant. (C) 2000 Federation of European Microbiological Societies. Published by El sevier Science B.V. All rights reserved.