Bioremediating Potentials of Marine Mercury-Resistant Bacteria on Polyaromatic Hydrocarbons Components of Bonny Light Crude Oil

Abstract

Aims: To evaluate the potentials of marine mercury-resistant bacteria isolated from the coastal water of Niger Delta region of Nigeria and examine their ability to tolerate, utilize and biodegrade Bonny light crude oil. Place and Duration of Study: The study was carried out at Onne light flow terminal sea port located in Eleme Local Government Area of Rivers State, Nigeria between August 2011 and February 2013. Methodology: The techniques employed for growth and biodegradation studies were total viable count, optical density and gas chromatographic analysis. Several bacterial genera capable of growing at 50 mg/l and higher concentrations of mercury were isolated and include: Acetobacterium, Arthrobacter, Planococcus, Brevibacterium, Alteromonas, Enterococcus and Cupriavidus.  Results: The result of total viable count, absorbance at 520 nm (OD520nm) and changes in Polyaromatic Hydrocarbons (PAHs) concentrations ranged from 5.88 - 6.45, 5.70 – 6.39 and 5.80 - 6.27 log10cfu/ml; 1.170 - 10.740, 0.880 - 10.210 and 0.460 - 10.090; and 64.779 mg/l - 29.777 mg/l, 128.103 mg/l‑74.107 mg/l and 82.085 mg/l‑68.809 mg/l respectively after 28 days of incubation period for the consortium (Acetobacterium woodii MRB I, Arthrobacter globiformis MRB VII and Cupriavidus necator MRB X), positive control (Pseudomonas aeruginosa) and Cupriavidus necator MRB X. Thus, Cupriavidus necator MRB X showed promising potentials in the bioremediation  of crude oil polluted environments and was almost comparable with standard strain Pseudomonas aeruginosa but the consortium were comparatively better and potent PAHs degraders of the Bonny light crude oil. Conclusion: This study has proved the bioremediating potentials of Mercury-resistant bacteria; therefore they could be used as potent bioremediating agents on Polyaromatic Hydrocarbons since their removal has been a challenge to environmental management.