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Ability of Gordonia alkanivorans strain 1B for enhanced desulfurization of dibenzothiophene and its derivatives using fructose as carbon source
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Abstract(s)
In order to keep up the strict sulfur limits on fossil fuels and their derivatives, refineries commonly use a desulfurization method, which combines high temperatures and pressures with molecular hydrogen known as hydrodesulfurization (HDS). However, the effectiveness of HDS to desulfurize recalcitrant organic aromatic compounds such as dibenzothiophene (DBT) or its derivatives is low. Biodesulfurization
(BDS) has been described as a promising complementary technique to HDS. Using microorganisms, BDS is able of desulfurize several recalcitrant compounds usually present in fossil fuels at mild temperatures and pressures without hydrogen, making it a simple and eco-friendly process. In this context and based in the fructophilic behavior of the desulfurizing bacterium, Gordonia alkanivorans strain 1B, several recalcitrant sulfur sources were tested in BDS assays using fructose as carbon source. So, strain 1B was used in desulfurization assays testing 4-mDBT, 4,6-dmDBT and 4,6-deDBT, as sulfur source, in comparison with DBT. Growth and desulfurization kinetics using the different sulfur sources were evaluated and the desulfurization rates were determined by GC analysis of x-DBT consumed. The results showed that the strain 1B using fructose as carbon source was able to fully desulfurize all the sulfur compounds tested in less than 121 hours. For 4-mDBT, 4,6-dmDBT and 4,6-deDBT the maximal bacterial growth rates obtained were 0.072 h-1, 0.069 h-1 and 0.095 h-1 with maximum desulfurization rates of 1.58, 4.84 and 4.30 umol g(DCW)-1 h-1, respectively. In comparison with previous results obtained for max of strain 1B in glucose as carbon source
and DBT as sulfur source (0.025 h-1), all the m_ max obtained in this study highlight once more the importance of use fructose as carbon source, independently of sulfur source. In addition, contrary to what has been described for other strains, the desulfurization rates obtained for the compounds with two alkyl groups were higher than for DBT (2.12 umol g(DCW)-1 h-1). In fructose, the desulfurization of 4,6-dmDBT and 4,6-deDBT by strain 1B were more than 2-fold in comparison with that for DBT. These promising results indicate the high potential of use this bacterium towards fossil fuels BDS.
Description
Keywords
Gordonia alkanivorans Dibenzothiophene Biodesulfurization Fossil fuels
Citation
Alves, L.; Silva, T.P.; Fernandes, A.S.; Paixão, S.M. - Ability of Gordonia alkanivorans strain 1B for enhanced desulfurization of dibenzothiophene and its derivatives using fructose as carbon source. In: RRB'10-10th International Conference on Renewable Resources and Biorefineries, Book of Abstracts, Poster 31, Valladolid, Spain, 4-6 June, 2014, p. 77