ABSTRACT
Biodegradation of polyaromatic hydrocarbons (PAHs) was performed using
hydrocarbon degrading bacteria isolated from Egyptian hydrocarbon polluted soil.
Naphthalene (Naph.) was considered as a model of diaromatic ring compounds,
while phenanthrene (Phn.) and anthracene (Anth.) were considered as models of
tricyclic aromatic hydrocarbons. Eight bacterial strains were isolated from different
collected oil polluted soil samples. Only two bacterial isolates; Pseudomonas
aeruginosa ALN6 and Brevibacterium casei ALN7 have shown an obvious
biodegradation potential of 99.90% and 99.97%, respectively on 1000ppm Phn. after
7 days of incubation. Biodegradation potentiality on Phn. was also examined using
PAHs mixture (Naph., Phn. and Anth.) in a total concentration of 1000ppm.
Brevibacterium casei ALN7 showed nearly the same biodegradation efficiency on
Phn. in both sole substrate and PAHs mixture systems (99.97% and 98.10%,
respectively). However, Pseudomonas aeruginosa ALN6 showed a great difference
on Phn. in sole substrate and PAHs systems (99.90% and 35.38%, respectively).
Biodegradation efficiency of both bacterial isolates was also examined on crude oil.
They both showed high biodegradation ability of 97% and 95% for Brevibacterium
casei ALN7 and Pseudomonas aeruginosa ALN6, respectively after four weeks of
incubation. However, ALN6 was superior for degrading normal and iso- paraffins
while ALN7 was superior for degrading unresolved complex mixture (UCM).