Using novel bacterial strains, scientists have successfully removed sulphur from fossil fuels such as petroleum and coal. Sulphur is one of the major pollutants emitted during the combustion of fossil fuels.
Scientists from CSIR-Institute of Minerals and Materials Technology (CSIR-IMMT) in Bhubaneswar used four bacterial strains that use dibenzothiophene (an organic sulphur compound which is a major contaminant of fossil fuel) as an energy source thereby getting rid of the sulphur.
To find novel bacterial strains that can selectively eliminate this organic sulphur, the researchers searched the microbial type culture collection (MTCC) of CSIR-IMTECH (Institute of Microbial Technology) and selected 10 bacterial strains with dsz genes.
“The dsz genes are central to sustainable bio-desulfurization. The presence of dsz genes and the metabolites which take part in desulfurization were first screened. We have also used bio-informatic tools for phylogenetic studies. More studies can reveal new bacterial species for desulfurization of coal,” says Madhabi M. Bhanjadeo, PhD scholar at the institute in an e-mail to The Hindu. Ms. Bhanjadeo is the first author of a paper published in the journal PLOS ONE.
The selected bacteria were grown in a medium supplemented with dibenzothiophene and other nutrients required for growth. They found that four bacteria were able to use almost 99% of the sulphur compound in just 10 days. The four strains are Rhodococcus rhodochrous, Arthrobacter sulfureou, Gordonia rubropertinita and Rhodococcus erythropolis.
“Since the sulphur-specific cleavage is vital for organic sulphur removal, we explored potential bacterial strains that desulphurise through a specific pathway (4-S pathway). Usual end products of this pathway are 2-hydroxy biphenyl and sulphate ions but in our study two of the bacterial strains are devoid of these end products, suggesting a variation in the pathway. The novel bacteria hold hidden pathways that we are yet to be explored,” says Dr. Umakanta Subudhi, from CSIR-IMMT and corresponding author of the paper.
The new process is also eco-friendly and economical, and these new bacterial strains can be potentially explored for the removal of sulphur from fossil fuels on a commercial scale.