Biodesulfurization of Thiophenic Compounds by a 2-Hydroxybiphenyl-Resistant Gordonia sp. HS126-4N Carrying dszABC Genes

Abstract

Microorganisms can metabolize or transform a range of known chemical compounds present in fossil fuels by naturally having highly specific metabolic activities. In this context, the microbial desulfurization of fuels is an attractive and alternative process to the conventional hydrodesulfurization (HDS) process, since the thiophenic sulfur containing compounds such as dibenzothiophene (DBT) and benzothiophene (BT) cannot be removed by HDS. A DBT desulfurizing mesophilic bacterium, identified on the basis of 16S rRNA gene sequence as Gordonia sp. HS126-4N (source: periphery soil of a coal heap) has been evaluated for its biodesulfurization traits and potential to desulfurize the thiophenic compounds. The HPLC and LC/MS analyses of the metabolites produced from DBT desulfurization and PCR-based nucleotide sequence confirmation of the key desulfurizing genes (dszA/dszB/dszC) proved that HS126-4N could convert DBT to 2-hydroxybiphenyl (2-HBP) via the 4S pathway. The isolate could convert 0.2 mM of DBT to 2-HBP within 48 h and was reasonably tolerant against the inhibitory effect of 2-HBP (retained 70% of growth at 0.5 mM 2-HBP). The isolated biocatalyst desulfurized/degraded 100% of 0.2 mM of 4-methyl DBT, 2,8-dimethyl DBT, BT and 3-methyl BT within 108 h. The capabilities to survive and desulfurize a broad range of thiophenic sulfur containing substrates as well as less inhibition by the 2-HBP suggest that HS126-4N could be a potential candidate for improved biodesulfurization/organic sulfur removal from fossil fuels.

Genomic analysis provides insights into the Gordonia sp. W3S5 taxonomy and sulfur metabolism-related genes

“…W3S5 used in this study was isolated from oil-contaminated soil samples collected from a local oil drilling company (OGDCL-Rajian Oil Field, Chakwal, Pakistan). A chemically defined medium (MG medium) used for growth and other experimental schemes contained 2.0 g KH 2 PO 4 , 4.0 g K 2 HPO 4 , 1.0 g NH 4 Cl, 0.2 g MgCl 2 •6H 2 O, 5.0 g glucose, 10.0 ml metal solution, and 1.0 ml vitamin mixture in 1000 ml distilled water (pH 7.0) (Akhtar et al 2018). The enriched culture was evaluated for its desulfurization activity by Gibbs test as described by Akhtar et al 2009.…”

“…In the current scenario, the biodesulfurization is a recommended approach to remove sulfur from complex compounds like dibenzothiophene (DBT), benzothiophene (BT), or their alkylated forms (Cx-DBTS, Cx-BTS) under mild conditions (Mohebali and Ball 2008;Akhtar et al 2018). However, due to limited knowledge on desulfurizing traits of the bacterial species, the large-scale process has not been developed (Akhtar et al 2019;Parveen et al 2020).…”

Biodesulfurization of Petro-diesel by a Novel Hydrocarbon Tolerable Paenibacillus glucanolyticus HN4

“…KT462, Rhodococcus erythropolis KA2-5-1, Gordonia sp. HS126-4 N and SC-10, Sphingomonas subarctica T7b, Mycobacterium goodii X7B and Bacillus subtilis WU-S2B [11,[31][32][33][34][35][36]. It is also known that high molecular weight alkylated DBTs, especially those alkylated at the 4and/or 6-position are difficult to be biodesulfurized by most of the biodesulfurizing microorganisms [1].…”

Biodesulfurization of Dibenzothiophene and Its Alkylated Derivatives in a Two-Phase Bubble Column Bioreactor by Resting Cells of Rhodococcus erythropolis IGTS8

“…Strains from the aforementioned bacterial genera have been used in BDS processes, employing growing or resting cells (whole cells), in both aqueous and biphasic systems [7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

“…Processes 2021, 9, x FOR PEER REVIEW 3 of 2 [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. According to Mohabeli and Ball [1], the utilization of active resting cells with th ability to desulfurize a wide range of organic sulfur compounds, placed in a biphasic sys tem, is the preferable configuration in order to make a BDS process competitive with deep HDS.…”