Abstract:
As Polycyclic Aromatic Hydrocarbons (PAHs) are biological
hazards in the environment, the aim of the present investigation is to
review their sources, biological and chemical properties and their biodegradation
by microorganisms in the soil. The complete degradation of PAHs that originate
from various sources require a community of microorganisms. When PAHs
are taken by microorganisms, they will be activated in aerobic metabolism
by insertion of two oxygen atoms by bacteria and green algae to produce
either cis-dihydrodiols or phenols. PAHs may also be activated by cytochrome
P450 of many fungi and bacteria to produce arene oxides.The
activation may also be performed by lignin degrading enzymes to produce
quinines. After complete degradation of PAHS in soil, it was found that
about 56-77% of the carbon of PAHs is converted to CO2, 16-35%
to microbial biomass and small portion accumulates as intermediate metabolites.
It can be concluded that the microbial decontamination of PAHs contaminated
soil is an efficient, economic and a good alternative to physiochemical
treatments if suitable conditions for the microorganisms are prevailing.
Subscribe Today 
