Thermophilic desulfurization of dibenzothiophene and different petroleum oils by Klebsiella sp. 13T

Purpose

Biodesulfurization (BDS) has the potential to desulfurize dibenzothiophene (DBT) and its alkylated derivatives, the compounds that are otherwise refractory to hydrodesulfurization (HDS). Thermophilic microorganisms are more appropriate to be used for BDS applications following HDS. The aim of the present study was to isolate a thermophilic microorganism and to explore its commercial relevance for BDS process.

Methods

The desulfurizing thermophilic strain was isolated and enriched from various soil and water samples using sulfur free medium (SFM) supplemented with DBT. Microbiological and genomic approach was used to characterize the strain. Desulfurization reactions were carried out using DBT and petroleum oils at 45°C followed by different analytical procedures.

Results

We report the isolation of a thermophilic bacterium Klebsiella sp. 13T from contaminated soils collected from petroleum refinery. HPLC analysis revealed that Klebsiella sp. 13T could desulfurize DBT to 2-hydroxybiphenyl (2-HBP) at 45°C through 4S pathway. In addition, adapted cells of Klebsiella sp. 13T were found to remove 22?C53% of sulfur from different petroleum oils with highest sulfur removal from light crude oil.

Conclusion

Klebsiella sp. 13T is a potential candidate for BDS because of its thermophilic nature and capability to desulfurize petroleum oils.