Journal of Environmental Biology

Bioremediation of polycyclic aromatic hydrocarbons by

Acinetobacter species isolated from ecological sources

H.T. Al-Hadithi¹, E.A. Al-Razzaq² and G.F. Fadhil³*

¹Department of Basic Pharmaceutical Sciences, University of Isra, College of Pharmacy, Amman, 11622, Jordan

²Department of Biology, College of Science, University of Basrah, Basrah, 61009, Iraq

³Department of Chemistry, College of Science, University of Duhok, Duhok, 1048BD, Iraq

*Corresponding Author E-mail: ghazwan.fadhil@uod.ac

Key words

Acinetobacter species,

Bioremediation,

Polycyclic aromatic hydrocarbons 

Publication Data

Paper received : 20.07.2016

Revised received : 21.12.2016

Re-revised received : 01.03.2017

Accepted : 09.03.2017?

Abstract

Aim: The objective of the present study was to isolate Acinetobacter from ecological sources in Basrah city, the Iraq?s main port located on the Shatt al-Arab, to identify recovered species and to investigate their capability for bioremediation and degradation of Polycyclic aromatic hydrocarbons (PAH).

Methodology: One hundred and five samples were collected from Municipal drinking water, soil and surface water of Shat Al-Arab waterway area / Basrah / Iraq, polluted with diesel oil. Two species of Acinetobacter were isolated and identified according to diagnostic tests. Bioremediation of PAHs was investigated by incubating? 5 x108 bacterial cell ml^-1 of either two species in a mineral medium and examined after two weeks, one month and two months adopting gravimetric and spectrophotometric methods. The bacterial density of each species was determined after each incubation period.

Results: Ten Acinetobacter isolates were obtained in a frequency distribution of 9.2523%. Isolates were isolated from three sources and? identified as A. lwoffii (8%), however, A. calocoacetcus (2%) was isolated from soil only. Starting with 5x10⁸ bacterial cell ml^-1 of A. calocoacetcus; the count was increased to 8.05x10¹¹cell ml^-1 after two weeks then decreased to 6.3x10⁵ cell ml^-1 after one month and became 0.2x10² bacterial cell ml^-1 after two months. Accordingly, the weight of PAHs decreased from 0.1 g to 0.053, 0.013 then to 0.001 g 250 ml^-1 respectively. The same sequence of events was demonstrated by A. lwoffii, though with a higher rate of degradation confirming its higher potency for bioremediation. ?????

Interpretation: Owing to bioremediation, the weight of PAH decreased with a concomitant decrease in the growth and activity of either species of Acinetobacter. Hence, it is a promising alternative for cleaning oil spills and reducing the concentration and toxicity of pollutants.

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