This study was undertaken to examine the effect of three structurally
related, non-ionic surfactants, Triton X-45, Triton X-100 and Triton X
-165, as well as the oleophilic fertilizer, Inipol EAP 22, on the rate
of biodegradation of phenanthrene by pure bacterial cultures. Each su
rfactant dramatically increased the apparent aqueous solubility of phe
nanthrene. Model studies were conducted to investigate the ability of
these surfactants to enhance the rate of transport and uptake of polyc
yclic aromatic hydrocarbons into bacterial cells, and to assess the im
pact that increasing the aqueous solubility of hydrocarbons has on the
ir rate of biodegradation. Our results indicate that increasing the ap
parent aqueous solubility of hydrocarbons can lead to enhanced biodegr
adation rates by two Pseudomonas saccharophila strains. However, our e
xperiments also suggest that some surfactants can inhibit aromatic hyd
rocarbon biodegradation by certain bacteria. Our data also support the
hypothesis that surface-active components present in the oleophilic f
ertilizer formulation, Inipol EAP 22, may have significantly contribut
ed to the positive results reported in tests of remedial agent impact
on bioremediation, which was used as a supplemental clean-up technolog
y on Exxon Valdez crude oil-contaminated Alaskan beaches.