Bacterial biodegradation of aliphatic sulfides under aerobic carbon- or sulfur-limited growth conditions

Abstract

Aims: To isolate bacteria capable of cleaving aliphatic carbon-sulfur bonds as potential biological upgrading catalysts for the reduction of molecular weight and viscosity in heavy crude oil. Methods and Results: Thirty-one bacterial strains isolated from enrichment cultures were able to biotransform model compounds representing the aliphatic sulfide bridges found in asphaltenes. Using gas chromatography and mass spectrometry, three types of attack were identified: alkyl chain degradation, allowing use as a carbon source; nonspecific sulfur oxidation; and sulfur-specific oxidation and carbon-sulfur bond cleavage, allowing use as a sulfur source. Di-n-octyl sulfide degradation produced octylthio-and octylsulfonyl-alkanoic acids, consistent with terminal oxidation followed by b-oxidation reactions. Utilization of dibenzyl sulfide or 1,4-dithiane as a sulfur source was regulated by sulfate, indicating a sulfur-specific activity rather than nonspecific oxidation. Finally, several isolates were also able to use dibenzothiophene as a sulfur source, and this was the preferred organic sulfur substrate for one isolate. Conclusions: The use of commercially available alkyl sulfides in enrichment cultures gave isolates that followed a range of metabolic pathways, not just sulfur-specific attack. Significance and Impact of the Study: These results give new insight into biodegradation of organosulfur compounds from petroleum and for biotreatment of such compounds in chemical munitions.

Unravelling the complete genome sequence of Advenella mimigardefordensis strain DPN7T and novel insights in the catabolism of the xenobiotic polythioester precursor 3,3′-dithiodipropionate

“…The microbial degradation of either naturally occurring or xenobiotic pollutant OSCs such as dibenzothiophene (McFarland, 1999), di-n-octylsulfide (Kirkwood et al, 2005), dimethylsulfoniopropionic acid (Yoch, 2002) or various C2- (Cook & Denger, 2002) and C3-sulfonates (Cook et al, 2006) has been studied in detail, and the metabolism of OSCs is an essential part of the global sulfur cycle (Sievert et al, 2007). During microbial utilization of DTDP as the sole carbon source, the excess sulfur was abstracted from 3SP-CoA as sulfite (Schürmann et al, 2013).…”

Sulfur from benzothiophene and alkylbenzothiophenes supports growth of Rhodococcus sp. strain JVH1

“…The effect of sulfate concentration on the degradation of organic sulfur compounds can be used as an indicator of sulfur-specific activity (Kirkwood et al, 2005), because the presence of sulfate typically results in repression of the ability to use alternate sulfur sources (Serbolisca et al, 1999;van der Ploeg et al, 2001). The desulfurization of aliphatic sulfides by Rhodococcus sp.…”

“…Sulfate-free mineral medium with acetate (SFMM) was prepared in acid-washed glassware as previously described (Kirkwood et al, 2005).…”

Biodesulfurization of benzonaphthothiophene by an isolated Gordonia sp. IITR100

“…strain K1bD could mediate the desulfurization of DBT and 1,4-dithiane, when these were present individually in the growth medium. But, when the two were provided together only the desulfurization of DBT was observed (Kirkwood et al, 2005). Similarly, the desulfurization of benzothiophene or 1,4-dithiane, by Rhodococcus sp.…”