For mineralization experiments, a mixture of octadecane
and [14C]octadecane (1.55 g/liter; specific activity, 0.37 ,uCi/
mmol) was used to coat the bottom of modified 125-ml
micro-Fembach flasks (Wheaton, Milville, N.J.), designed
for the collection of 14C02 and 14C-volatile compounds (15).
The solvent was evaporated, and 20 ml of mineral salts
medium (16) containing rhamnolipid was added to each flask.
The octadecane was melted and the flasks were inoculated
and incubated as described above. The micro-Fernbach
flasks were periodicallyv flushed through a series of six traps
to collect '4C02 and 1 C-volatile organic compounds (15).