Pilot-scale biodesulfurization of natural gas: microbial ecology and community dynamics of an in situ enriched system

This study investigated the microbial ecology of a biodesulfurization system inoculated with indigenous (rather than commercial) sulfur-oxidizing bacteria (SOB), aiming to assess their rapid enrichment feasibility and identify optimization strategies.

Pilot-scale Shell-Paques reactors were established to remove hydrogen sulfide from natural gas, using an inoculum of indigenous SOB. Microbial community dynamics were tracked via high-throughput sequencing, while ecological interactions were analyzed by combining co-occurrence network analysis and niche overlap indices. Indigenous SOB were successfully enriched to an abundance of ∼30% within 13 days. Thioalkalimicrobium emerged as the dominant SOB genus, differing from strains typically employed in commercial technologies. A key finding was the production of bipyramidal elemental sulfur with a rhombic structure as the primary product. Both network and niche overlap analyses revealed complex ecological interactions, indicating potential competition and mutualism between Thioalkalimicrobium and other dominant genera.

Indigenous SOB can be rapidly enriched within two weeks to achieve effective desulfurization and sulfur recovery. The ecological insights lay the groundwork for optimizing enrichment through targeted microbiota management.