Biodegradation Potential of Bacteria Isolated from Crude Oil Polluted Site in South South, Nigeria

Aims: This study aimed to determine the biodegradative potential of crude oil by Chryseobacterium sp. and Lysinibacillus fusiformis isolated from Crude Oil site in Gokana LGA, of Rivers State.

Study Design: Research was designed to evaluate the speed of degradation of crude oil by bacterial species over a period of 28 days.

Place and Duration of Study: Study was carried out in the Microbiology Laboratory of Rivers State University from March to April 2018.

Methodology: Four experimental set ups were used: mineral salt broth with crude oil only (Control), Chryseobacterium sp. in mineral salt culture with crude oil (Set-up 1), Lysinibacillus fusiformis in mineral salt culture with crude oil (Set-up 2) and Chryseobacterium sp.+Lysinibacillus fusiformis in mineral salt culture with crude oil (Set-up 3). Analysis of pH and Total Viable Counts was carried out at weekly intervals while Total Petroleum Hydrocarbon was carried out at bi-weekly intervals.

Results: Results showed a steady decline in pH from almost neutral (6.1) to acidic with mixed culture set up having the lowest value of 4.19 < Lysinibacillus fusiformis set up of 4.22 < Chryseobacterium sp. set up of 4.34. Total Petroleum Hydrocarbon followed the same trend of steady decline from 74.8 mg/L with Lysinibacillus fusiformis species having the least value of 40.44 mg/L < mixed culture of 44.85 mg/L < Chryseobacterium sp. of 51.08 mg/L. Total Viable Counts (Log10 cfu/mL) of bacteria showed increase in growth in all set ups. Lysinibacillus fusiformis increased from 5.10±0.01 to 6.85±0.05 > the consortium increased from 5.21±0.01 to 6.84±0.04 > Chryseobacterium sp. increased from 5.30±0.01 to 6.73±0.06 from beginning to end of the experiment.

Conclusion: Results showed that Lysinibacillus fusiformis had greater capacity to degrade crude oil, followed by the mixed culture and lastly, Chryseobacterium sp. These bacterial species can be harnessed and used for clean-up of crude oil contaminated environment.