| description |
After the first commercial applications of a new biological process to remove hydrogen sulfide (H2S) from low pressure biogas, the need arose to broaden the operating window to enable the removal of organosulfur compounds from high pressure sour gases. In this study we selected microorganisms, from a full-scale biodesulfurization system, that are capable of withstanding the presence of thiols. This full-scale unit has been in stable operation for more than 10 years. We investigated the microbial community by using next-generation sequencing of 16S rRNA gene amplicons which showed that methanethiol gave a competitive advantage to bacteria belonging to the genera Thioalkalibacter (Halothiobacillaceae family) and Alkalilimnicola (Ectothiorhosdospiraceae family). The sulfide-oxidizing potential of the acclimatized population was investigated under elevated thiol loading rates (4.5 - 9.1 mM d-1), consisting of a combination of methanethiol, ethanethiol, and propanethiol. With this biomass, it was possible to reach a stable bioreactor operation at which 80% of the supplied H2S (up to 61 mM d-1) was oxidized to elemental sulfur. Moreover, it was found that a conventionally applied method to control oxygen supply to the bioreactor, i.e. by maintaining a redox potential set-point value, appeared to be ineffective in the presence of thiols. |