International Journal of Marine Science, 2017, Vol.7, No.42, 399-410
399
Research Article Open Access
Estimation of Bacterial Biodegradability of PAH in Khor Al-Zubair Channel,
Southern Iraq
Fadhil N.A. Alkanany, Satar A. Gmais, Anwar A. Maki, Asaad M.R. Altaee
Marine Science Center, University of Basra, Iraq
Corresponding author email
International Journal of Marine Science, 2017, Vol 7, No 42 doi
Received: 01 Sep., 2017
Accepted: 27 Sep., 2017
Published: 20 Oct., 2017
Copyright © 2017
Alkanany et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Alkanany F.N.A., Gmais S.A., Maki A.A., and Altaee A.M.R., 2017, Estimation of bacterial biodegradability of PAH in Khor Al-Zubair channel, Southern Iraq,
International Journal of Marine Science, 7(42): 399-410 (doi
Abstract
Four bacterial strains were isolated from Khor Al-Zubair channel, southern Iraq based on a high growth rate on crude oil
and on hydrocarbon degradation ability. The strains were preliminarily identified based on morphological observation, and by the
Vitek II system. The isolates were identified as
Brevundimonas diminuta /vesicularis
,
Vibrio vulnificus
,
Sphingomonas paucimobilis
and
Ochrobactrum anthropic
. However, the ability of these strains to utilize crude oil (0.25%; 0.5%; 1% and 2% v/v) varied both
in rates of utilization and in growth profiles. The components of crude oil degraded by the isolates were determined by capillary
gas chromatography.
Sphingomonas paucimobilis
and
Vibrio vulnificus
were the most effective bacteria degrade PAH on seventh day
incubation, especially in concentration 2.0 mg/l (97.39% and 84.23%) respectively, meanwhile,
Brevundimonas diminuta/ vesicularis
was highly effective degrade PAH (73.41% and 62.08%) in concentration 1.0 and 0.5 mg/l, respectively. On the other hand,
Ochrobactrum anthropi
was the lowest in all concentrations.
Keywords
Khor Al-Zubair; Bacteria; Vitek II system; Gas chromatography
Introduction
Polycyclic aromatic hydrocarbons (PAHs) are compounds consisting of two or more aromatic rings, the
USEPA has reported sixteen unsubstituted PAHs as main concern pollutants, eight of them may be human
carcinogens (Yan et al., 2004). The concern is that some PAHs are toxic, carcinogenic or teratogenic. PAHs are a
resource of carbon and energy and being exploited by some bacteria as growth substrates. The presence of PAH in
the marine environment is largely attributed to oil spills, discharge and natural river infiltration, import or transfer
of airflow. Therefore, global increased human activity has increased risks to the marine environment (Latimer
and Zheng, 2003).
PAHs are present as small and large, depending on the number of rings. "Small" PAHs contain up to six
condensed aromatic rings, whereas, "large" PAHs containing more than six aromatic rings, which are less soluble
in water and less volatile (Kumar et al.,
2011).
Although PAHs fact that undergo oxidation, photolysis, bioaccumulation, volatilization and adsorption in the
environment, but have been microbial degradation and transformation as the key processes identified for the
removal of pollutants (Zeng et al., 2010).
Biodegradation is a viable bioremediation technology for organic pollutants. It has identified that microorganism
degrade ecological pollutant in various environments. Bioremediation uses the metabolic adaptation of
microorganism to degrade contaminations. Bioremediation is a promising approach, as it employs microorganisms
to degrade or remove different pollutants, such as organic compounds into harmless metabolites or mineralize the
contaminants to CO
2
and water (Alexander et al., 1985).
The rate of biodegradation depends on pH, temperature, microbial population, oxygen, nutrient accessibility,
chemical structure of the compound, the division of properties and cellular chemical transport in the growth
medium (Singh and Ward, 2004). The aim of the present study was to isolate and identify new bacteria that have
the ability to degrade polycyclic aromatic hydrocarbons.
