Isolation and Characterization of Oil-Degrading Bacteria from One of South Sumatera’s Oilfield

Microbial Enhanced Oil Recovery (MEOR) is a tertiary oil recovery method that utilizes microbes to enhance oil production. This research was focused on the isolation and characterization of indigenous bacteria from a South Sumatra’s oilfield which were able to degrade heavy crude oil and decrease oil viscosity. The total of 33 colonies were successfully isolated based on sequential isolation method and screened based on oil degradation activity and SARA analysis. Isolate G3, G7, and N6 were choosen as the best candidate as they were able to reduce oil viscosity up to 22,67%; 23,14%; and 24,36% respectively. Based on 16S rRNA analysis, isolate G3 which was able to degrade aromatic fraction (38,27%) and resin (29,26%) was identified as Pseudoxhantomonas taiwanensis. Isolate G7 which degraded aromatic fraction (61,14%) was identified as Brevibacillus agri while N6 which degraded asphaltene fraction (51.76%) was identified as Bacillus subtilis. In addition, the change in nalkana fraction (C11 – C28) abundance relative to phytan showed that all of the bacterial isolates were able to change those fractions of crude oil. This study showed that three bacterial species isolated from South Sumatran Oilfield were able to degrade heavier fraction of crude oil and reduce its viscosity. This result suggests that those bacteria are highly potential to be applied for MEOR technology.