Remediation of PAH-Contaminated Soils and Sediments: A ...

in contaminated soils than uncontaminated soils (Carmichael and Pfaender,
1997).
Before discussing remediation techniques, it is important to identify the different
microorganisms capable of degrading PAHs. Bacterial, fungal and algal species
have been found to degrade PAH compounds, with bacteria constituting the most
important group of degraders (Cerniglia et al., 1992; Kastner et al., 1994).
Numerous bacteria genera and species can degrade 2- or 3-ring PAHs have
been identified, but few genera have shown ability to degrade HMW PAHs (Table
3). However, some Pseudomonas species have been found to degrade 4-ring
and 5-ring PAHs (Juhasz and Naidu, 2000).
Table 3. Some genera of PAH-degrading microorganisms (adapted from Frick
et al., 1999).
Bacteria
PAH compounds degraded
Acidovorax phenanthrene, anthracene
Alcaligenes phenanthrene, fluorene, fluoranthene
Arthrobacter benzene, naphthalene, phenanthrene
Mycobacterium phenanthrene, pyrene, benzo[a]pyrene,
Pseudomonas phenanthrene, fluoranthene, fluorene, benzo[a]pyrene
Rhodococcus pyrene, benzo[a]pyrene
Sphingomonas phenanthrene, fluoranthene, anthracene
The following studies are examples of biodegradation research:
� Liste and Felgentreu (2006) observed similar microbial species richness
between a contaminated and pristine soil; however, PAH degraders
(Alcaligenes piechaudii, Pseudomonas putida, and Stenotrophomonas
maltophilia) were more abundant in the contaminated soil (1517 mg kg -1
total petroleum hydrocarbons; 71.4 mg kg -1 total PAHs) compared to
pristine soil.
� Mueller et al. (1997) reported bacterial ability to degrade PAHs isolated
from creosote-contaminated soils in the United States, Norway, and
Germany. Sphingomonas strains showed the most ability to degrade 4- &
5-ring PAH.
� Kanaly and Harayama (2000) found that Sphingomonas species used
compounds like fluoranthene and phenanthrene as a sole carbon source,
while a Mycobacterium strain from PAH-contaminated freshwater
sediments was capable of using phenanthrene, pyrene, and fluoranthene
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