Enhanced Biodegradation of Degreaser Using Pseudomonas and Bacillus Species in Fresh Water Ecosystem

Aim: The aim of this study is to enhance the biodegradation of degreasers used in upstream sectors of Nigeria Petroleum Industry using bio-augmenting organisms such as: Pseudomonas and Bacillus species in freshwater Ecosystem.

Study Design: This study employs experimental designs, Randomized Block Design treatment set up, statistical analysis of data and interpretation.

Place and Duration of Study: Freshwater sample for this research was collected from Asarama Andoni, in Rivers State, Nigeria. The study lasted for six months.

Methodology: The experimental set-up was carried in 500 ml conical flask with two species of bacteria, two types of degreaser and fresh water sample giving a total of 8 set-up including controls. The Pseudomonas and Bacillus species used in this study were isolated from the freshwater ecosystem and identified using standard microbiological methods. The bioremediation potential of the respective test organisms were monitored at ambient temperature 28±0.2°C for 28 days at a constant interval of 7 days using the following Physiochemical parameter; Total dissolved Solid, Hydrogen concentrations ions and Total Hydrocarbon Content. While the following Microbiological parameters; Total heterotrophic Bacteria, Total Heterotrophic Fungi, Hydrocarbon Utilizing Bacteria, and Hydrocarbon Utilizing Fungi were monitored.

Results: The percentage of degradability of the respective set-ups ranged from Control (Rigwash) (3.29%) < Pseudomonas sp. + Rigwash (27.56%) < Pseudomonas + Bacillus + Rigwash< (31.57%), Bacillus sp.+ Rigwash (37.57%) Control 2 (Aquabreak) (9.45%) < Pseudomonas sp.+ Aquabreak (26.77%) < Pseudomonas + Bacillus + Aquabreak (31.32%)< Bacillus sp.+ Aquabreak (32.46%). Overall evaluation revealed that Bacillus sp. had a higher biodegradation potential on both degreaser (Rigwash and Aquabreak) in freshwater than Pseudomonas sp. Five species of bacteria: Escherichia coli, Micrococcus, Citrobacter, Bacillus, and Pseudomonas species and four fungal species: Penicillium, Mucor, Aspergillus and Rhizopus species were isolated and identified as hydrocarbon utilizing bacteria and fungi organisms respectively.

Conclusion: The results revealed that Bacillus species have more degradability potential than Pseudomonas species for both Aquabreak and Rigwash. These results also indicated the low biodegradation potential of Rigwash in fresh Ecosystem.