[Isolation of viscous-oil degrading microorganism and biodegradation to resin]

Abstract

Objective: The aim of this study was to isolate bacterial strains with high-efficiency to degrade resins.

Methods: We used resin-plate to isolate resin-degrading bacteria from the formation water of Nanbao35-2 oil field, China National Offshore Oil Corporation. The morphological properties and the sequence homology of 16S rRNA were used to identify the strains. The changes of four fractions contents and the infrared spectrometry of the heavy oil were used to analyze the degradation properties.

Results: Four strains, Q4, QB9, QB26 and QB36, were isolated using resin as the sole carbon source. Based on the high sequence similarities (more than 99%) of 16S rDNA sequences analysis. These strains were identified as member of the Petrobacter sp., Geobacillus stearothermophilus, Bacillus licheniformis, Geobacillus pallidus, respectively. QB26, a Bacillus licheniformis, was the most efficient strain, it can grow well under anaerobic conditions, emulsify heavy oil well, and degrade resin and asphaltene in heavy oil. The relative content of saturated hydrocarbons in heavy oil increase after degradation, and the relative content of resin and asphaltene in heavy oil decreased 5.1% and 2.7%, respectively.

Conclusion: The strains isolated from Nanbao 35-2 oil field formation water could degrade resin and heavy oil. They have potential values in microbial enhanced oil recovery and oil pollution treatment.