Petroleum Contaminated Seawater Detoxification in Microcosm by Halotolerant Consortium Isolated from Persian Gulf

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Petroleum Contaminated Seawater Detoxification in Microcosm by Halotolerant Consortium Isolated from Persian Gulf Mahboobeh Dehvari1 · Shokouh Ghafari1 · Neamat Jaafarzadeh Haghighifard1 · Sahand Jorfi1 Received: 4 June 2020 / Accepted: 21 October 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Bioremediation of a petroleum contaminated seawater from Persian Gulf was investigated and efficiency of natural attenuation by native halotolerant bacterial consortium, biostimulation by addition of macro nutrients (nitrogen and phosphorus) and surfactant and bioaugmentation by application of halotolerant hydrocarbon degrading strains were evaluated. Biodegradation rates in defined conditions were studied for 30 days. Four pure isolates including Bacillus sp. PG-1, Pseudomonas aeruginosa PG-2, Paenibacillus lautus PG-3, and Pseudomonas putida PG-4 were used to preparation of bacterial consortium. Results indicated that the bioaugmentation yielded the best TPH removal efficiency of 56.24%, followed by biostimulation with surfactant addition (removal of 31.52%). The most bacterial density was also observed for bioaugmentation bioreactor. Toxicity of reaction medium was evaluated by oxygen consumption rate inhibition, dehydrogenase activity inhibition and growth rate inhibition methods in which, the least toxicity rates of 27%, 25% and 31% were observed for bioaugmentation based bioreactor, respectively. Simultaneous bioaugmentation and biostimulation can efficiently reduce the crude oil content in the surface of seawater using halotolerant strains.

Introduction The need for energy and consequently petroleum and its derivate has been increased dramatically [1]. World has experienced the greatest economic growth and industrial development and therefore fossil fuels are forefront of energy matrix at the present time [2]. Exploration, drilling and transportation of crude oil have also been responsible for the occurrence of environmental problems, especially oil spill events which are among the most important current concerns and challenges [3]. Contamination of marine environments caused by oil spills has been reported repeatedly [4, 5]. Major oil fields are located in seas and on the other hand crude oil exploitation sites are frequently far from refineries and consumption areas, meaning that crude oil should be transported to its final destination and a major portion of this travel happens on the ocean [6]. The main routes of crude oil transportation are from the Middle East to Japan, from South America to Europe, and from Africa to the North America. In the Middle East, Persian Gulf is * Sahand Jorfi [email protected] 1



Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

the most marine environment affected by oil explorations and transportations [7]. This has led to sever contamination of seawater and adverse effects on biodiversity such as coral reefs [8]. Considering the above statement on crude oil contamination, marine environment are under constant risk of being damag