Effect of methanethiol on process performance, selectivity and diversity of sulfur-oxidizing bacteria in a dual bioreactor gas biodesulfurization system

• Published in: Journal of hazardous materials Vol. 398; p. 123002
• Main Authors: Kiragosyan, Karine, Picard, Magali, Timmers, Peer H.A., Sorokin, Dimitry Y., Klok, Johannes B.M., Roman, Pawel, Janssen, Albert J.H.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05-11-2020
• Subjects: Alkalilimnicola ehrlichii; Bacteria - genetics; Bioreactors; Ectothiorhodospiraceae; Gammaproteobacteria; Gases; Hydrogen Sulfide; Microbial dynamics; Oxidation-Reduction; Sulfhydryl Compounds; Sulfur; Thioalkalibacter halophilus; Thioalkalivibrio sulfidiphilus; Thiol toxicity; Alkalilimnicola ehrlichii; Thioalkalivibrio sulfidiphilus; Microbial dynamics; Thiol toxicity; Thioalkalibacter halophilus
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.123002

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•Added anaerobic bioreactor increased robustness of the gas biodesulfurization process.•System modification led to a higher sulfur yield in the presence of thiols.•This is caused by an increased abundance of thiol-resistant SOB.•Thioalkalibacter halophilus proliferated fast and became the most abundant species.•The electron donor in our experimental biodesulfurization setup was polysulfide.
This study provides important new insights on how to achieve high sulfur selectivities and stable gas biodesulfurization process operation in the presence of both methanethiol and H2S in the feed gas. On the basis of previous research, we hypothesized that a dual bioreactor lineup (with an added anaerobic bioreactor) would favor sulfur-oxidizing bacteria (SOB) that yield a higher sulfur selectivity. Therefore, the focus of the present study was to enrich thiol-resistant SOB that can withstand methanethiol, the most prevalent and toxic thiol in sulfur-containing industrial off gases. In addition, the effect of process conditions on the SOB population dynamics was investigated. The results confirmed that thiol-resistant SOB became dominant with a concomitant increase of the sulfur selectivity from 75 mol% to 90 mol% at a loading rate of 2 mM S methanethiol day−1. The abundant SOB in the inoculum – Thioalkalivibrio sulfidiphilus – was first outcompeted by Alkalilimnicola ehrlichii after which Thioalkalibacter halophilus eventually became the most abundant species. Furthermore, we found that the actual electron donor in our lab-scale biodesulfurization system was polysulfide, and not the primarily supplied sulfide.