Abstract
Bacterial isolates from a number of different soils were screened by growth observation and microscopic examination for Arthrobacter spp. Incidence of arthrobacter in the total population varied, but averaged around 15% in the soils investigated. One hundred and thirty arthrobacter isolates were tested for their ability to utilize aromatic hydrocarbons as their sole carbon source. Seventy-seven percent of these organisms were able to grow on at least two aromatic substrates and many were capable of growth on a wide range of these compounds. Nutritional studies indicated that arthrobacter with simple requirements were able to utilize the greatest number of aromatic hydrocarbons as their sole carbon source. The ability of the arthrobacter to metabolize aromatic compounds is discussed in terms of their possible role in the formation and turnover of residual soil organic matter.