Microalgal-Bacterial Consortium in Polyaromatic Hydrocarbon Degradation of Petroleum Based Effluent

The recurrent and indiscriminate discharge of flow stations' crude oil effluent has led to an increased polyaromatic hydrocarbons (PAHs) level in the environment. PAHs are high-priority environmental pollutants of significant human health concerns, thus considerable effort has been made in this study to biodegrade these PAHs using microalgalbacterial consortia. Crude oil effluent samples collected from the saver pit at Egbaoma flow station in the Niger Delta region of Nigeria were analysed biochemically and microbiologically. Three species of bacteria and two species of microalgae isolated, characterized and screened emerged as best hydrocarbon utilizers. The consortia comprised of Chlorella minutissimma and Aphanocapsa sp. as microalgae inoculants, while Citrobacter sp. SB9, Pseudomonas aeruginosa SA3 and Bacillus subtilis SA7 as bacterial inoculants. Growth dynamics, pH and degradation of the effluents' PAH content were analyzed for a period of ten days. Consortium BCC (bacteria inoculants and Chlorella minutissimma), BCCA (all inoculants) and BCA (bacteria inoculants and Aphanocapsa sp.) had PAH degradation percentage of 92.09%, 67.76% and 47.19% and optical density (OD) of 0.1255°A, 0.0669°A and 0.0703°A from an initial OD of 0.0126°A respectively. Only BCA had an acidic pH after ten days. Effective synergism and excellent PAH degradation is achievable and highly recommendable with microalgal-bacterial consortium yet its success is highly dependent on the consortium assembling, therefore, proper selection of the microbes for biodegradation is paramount to the success and efficiency of the degradation process.