Dibenzothiophene desulfurization capability and evolutionary divergence of newly isolated bacteria
- 338 Downloads
Metabolically microorganisms are diverse, and they are capable of transforming almost every known group of chemical compounds present in coal and oil in various forms. In this milieu, one of the important microbial metabolic processes is the biodesulfurization [cleavage of carbon–sulfur (C–S) bond] of thiophenic compounds, such as dibenzothiophene (DBT), which is the most abundant form of organic sulfur present in fossil fuels. In the current study, ten newly isolated bacterial isolates, designated as species of genera Gordonia, Amycolatopsis, Microbacterium and Mycobacterium, were enriched from different samples in the presence of DBT as a sole source of organic sulfur. The HPLC analysis of the DBT grown cultures indicated the consumption of DBT and accumulation of 2-hydroxybiphenyl (2-HBP). Detection of 2-HBP, a marker metabolite of 4S (sulfoxide–sulfone–sulfinate–sulfate) pathway, suggested that the newly isolated strains harbored metabolic activity for DBT desulfurization through the cleavage of C–S bond. The maximum 2-HBP formation rate was 3.5 µmol/g dry cell weight (DCW)/h. The phylogenetic analysis of the new isolates showed that they had diverse distribution within the phylogenetic tree and formed distinct clusters, suggesting that they might represent strains of already reported species or they were altogether new species. Estimates of evolutionary divergence showed high level of nucleotide divergence between the isolates within the same genus. The new isolates were able to use a range of heterocyclic sulfur compounds, thus making them suitable candidates for a robust biodesulfurization system for fossil fuels.
KeywordsDibenzothiophene Organic sulfur C–S bond cleavage 16S rRNA gene Phylogenetic analysis
This research work was supported by the International Foundation for Science, Stockholm, Sweden, through a grant to Dr. Nasrin Akhtar (Research Grant Agreement No. F/5379-1).
Compliance with ethical standards
Conflict of interests
The authors declare that they have no conflict of interests.
- Ausbel FM, Brent R, Kingston RE, Moore DD, Seidman JG, Smith JA, Struhl K (1995) Short protocols in molecular biology, 3rd edn. Wiley, New YorkGoogle Scholar
- Eriksen J (2008) Soil sulfur cycling in temperate agricultural system. In: Sulfur: a missing link between soils, crops, and nutrition. ASA-CSSA-SSSAGoogle Scholar
- Kilbane JJ (1991) Bacterial produced extracts and enzymes for cleavage of organic C–S bonds. European Patent No. 0445896A2Google Scholar
- Ting MA, Shanshan LI, Guoqiang LI, Renjing WANG, Fenglai LIANG, Rulin LIU (2006) Cloning and expressing DBT (dibenzothiophene) monooxygenase gene (dsz C) from Rhodococcus sp. DS-3 in Escherichia coli. Front Biol China 4:375–380Google Scholar