Many polycyclic aromatic hydrocarbons (PAHs) are known
to be mutagenic or carcinogenic, and their contamination
in soil and aquifer is of great environmental concern.
Limited numbers of microorganisms including mycobacteria,
Sphingomonas and white rot fungi were found to be capable
of degrading PAHs with four or more fused aromatic rings. In
white rot fungi, lignin peroxidases are believed to be involved
in the degradation of PAHs. In addition to these enzymes,
P450 monooxygenases in some fungi were implicated in the
degradation of PAHs. The stimulation of PAH biodegradation
by the addition of surfactants was observed with some of
these microorganisms although the agents were inhibitory
on biodegradation with some other microorganisms.
Mathematical models were constructed to explain the effect
of surfactants on biodegradation. Further studies should be
carried out to select the best microorganisms and surfactants
for applications to PAH bioremediation.