Physical state of phenanthrene for utilization by bacteria.

Experiments were done to determine if bacteria able to utilize phenanthrene as a sole source of carbon obtain the hydrocarbon directly from solid phenanthrene particles suspended in the medium or from the phenanthrene dissolved in the medium. Growth experiments were done in gas-tight fermentors completely filled with air-saturated, mineral salts solution with phenanthrene as the substrate. Generation times were determined by rate of oxygen consumption. Generation times were independent of the amount of solid phenanthrene present, and these generation times were the same as the generation time on medium containing only dissolved phenanthrene. It was concluded that bacteria utilize phenanthrene in the dissolved state.