189
International Journal of Marine Science, 2017, Vol.7, No.18, 176-182
176
Research Report Open Access
Biodegradation of Aliphatic Hydrocarbons by Bacteria Isolated from Khor
Al-Zubair Channel, Southern Iraq
Asaad M.R. Al-Taee
1
, Fadhil N. Alkanany
1
, Satar A. Gmais
1
, Hassan A.N. Alshawi
2
1 Marine science center, University of Basra, Iraq
2 Research and Quality Control, SOC, Iraq
Corresponding author email
International Journal of Marine Science, 2017, Vol.7, No.18 doi
Received: 24 Apr., 2017
Accepted: 01 Jun., 2017
Published: 15 Jun., 2017
Copyright© 2017
Al-Taee 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
:
Al-Taee A.M.R., Alkanany F.N., Gmais S.A., and Alshawi H.A.N., 2017, Biodegradation of aliphatic hydrocarbons by bacteria isolated from Khor Al-Zubair
channel, southern Iraq, International Journal of Marine Science, 7(18): 176-182 (doi
Abstract
Four bacterial strains capable of using crude oil as the sole carbon source were isolated from Khor Al-Zubair channel,
southern Iraq. The isolates were identified as
Vibrio vulnificus
;
Brevundimonas diminuta/vesicularis
;
Ochrobactrum anthropic
and
Sphingomonas paucimobilis
by the Vitek II system. The bacteria grew aerobically in liquid culture containing four concentrations
(0.25%, 0.5%, 1% and 2% v/v) of crude oil at 30ᵒC for a seven day period. The components of crude oil degraded by the isFolates were
determined by capillary gas chromatography.
Vibrio vulnificus
was the most effective bacteria to degrade crude oil, especially in
concentration 2% (93.05%). Meanwhile,
Ochrobactrum anthropi
was the lowest (9.63%) in concentration 0.25%.
Keywords
Khor Al-Zubair; Bacteria; Vitek 2 system; Gas Chromatography
Introduction
The constituents of crude oil can be classified to four fractions: saturates aromatics, resins and asphaltenes. Each
of these fractions contains a large number of compounds. Saturates is considered the major constituents of crude
oil according to their chemical structures into alkanes (paraffins) and cycloalkanes (naphthenes). Aromatic
hydrocarbons may have one or more aromatic rings with or without alkyl substitution(s). While, both the resin and
asphaltene fractions do not contain hydrocarbon polar compounds. The elements present in resins and asphaltenes,
in addition to carbon and hydrogen, are trace amounts of nitrogen, sulfur and/or oxygen (Harayama et al., 1999).
Petroleum hydrocarbons are the most common environmental pollutants in the world and oil spills pose a great
hazard to terrestrial and marine ecosystems. Oil pollution may arise either accidentally or operationally whenever
oil is produced, transported, stored and processed or used at sea or on land. Oil spills are a major menace to the
environment as they severely damage the surrounding ecosystems (Head et al., 2006; Emtiazi et al., 2009).
Xenobiotic pollutants like crude oil can be removed from the environment by Biodegradation mechanism of
naturally occurred microorganisms, this is the basic and save process (Cappello et al., 2007).
Because of the immiscibility of hydrocarbons in water, the growth of microorganisms on hydrocarbons is a
specific problem. Biosurfactants are surface agents which increase the cell-substrate adhesion, that leads to
emulsify hydrocarbons in solution, then the surface tension is reduced by biosurfactants due to its accumulation at
the immiscible fluids increasing the insoluble compounds surface area which leads to rasing bioavailability and
then hydrocarbons biodegradation (Batista et al., 2006).
The essential crude oil components are alkanes (Van Beilen et al., 2003). Some marine bacteria have the ability to
biodegradation of alkanes and these bacteria are important for marine environment (Kohno et al., 2002).
Due to lack of functional groups as well as very low water solubility, aliphatic hydrocarbons exhibit boths, low
chemical reactivity and bioavailability for microorganisms. However, some microorganisms possess the metabolic
capacity to use these compounds as carbon and energy sources for their growth (Berthe-Corti and Fetzner, 2002).
