Abstract
Petroleum hydrocarbons are major pollutants in marine environments. The present study describes the potential of a halothermophilic bacterial consortium capable of degrading polycyclic aromatic hydrocarbons (PAHs) in petroleum wastewater under extreme conditions. The consortium was enriched from brine originating from a desalination plant. The consortium efficiently degraded both the low molecular weight (LMW) PAHs-naphthalene (NAP), phenanthrene (PHN), anthracene (AN) and fluorene (FLU) as well as the high molecular weight (HMW) PAHs-pyrene (PY), benzo(e)pyrene (B(e)P). and benzo(k)fluoranthene (B(k)F), respectively. A nearly quantitative release of carbon dioxide (85 +/- 1.2%) in conjunction with significant reduction of PAH concentration and an increase in bacterial cell count (from 10(4) to 10(9) cfu/mL) pointed at mineralization of PHN. The consortium was able degrade 86 +/- 2.7% and 58 +/- 4.1% of PHN (200 ppm) at 20% and 30% NaCI concentration respectively. Co-metabolism with PHN thereby enhanced the degradation of HMW PAHs. In petroleum refinery wastewater the PAHs were potently degraded by the bacterial consortium with 94 +/- 3.8% COD removal in a continuous stirred tank reactor. Ochrobactrum halosaudia strain AJH1, Ochrobactrum halosaudia strain AJH2 and Pseudomonas aeruginosa strain AJH3 were present in the PAH-degrading halothermophilic consortium. (C) 2017 Elsevier Ltd. All rights reserved.