The Molecular Succession of Bacterial Community of Crude Oil Polluted Soil and Water Samples from the Niger Delta, Nigeria

A study was conducted on molecular succession of bacterial community to show their response to oil spill. Crude oil contaminated soil and water samples were obtained from Agbada-Aluu, Obite, and Bonny in Rivers State, Nigeria. The PCR-DGGE method was used to generate complex molecular profile analysis of the polluted sites microbiota. The growth dynamics of the bacteria was determined by the degrading activity, bacterial population and the pH of the culture media (Bushnell-Haas broth supplemented with 2% v/v crude oil). On day 35, Bonny soil had the highest bacterial load of (17.67 ± 1.25) x104 Cfu/mL. The highest bacterial population for the mixed cultures of each sample was observed on day 7. The bacteria in Obite soil demonstrated the greatest ability to degrade crude oil with degrading activity of 246.28 ± 3.4 Units/Hr on day 7 while the lowest degrading activity of 0.9 ± 1.2 Units/Hr was obtained with Obite water and Bonny soil on days 28 and 35 respectively. The pH values (6.8 - 8.2) were slightly basic throughout the incubation period of 35 days. The PCR-DGGE showed that there were shifts in the bacterial community during the 35 days of incubation, showing that the oil affected the bacterial community. The DNA bands that showed dominancy throughout the incubation period indicates the bacteria that played a major role in the degradation of the oil which is vital for their metabolism.