inhibbimus

Inhibbimus is a genus of Gram-negative, obligate anaerobic bacteria that was first described in 2021 within the family Enterobacteriaceae. Members of this genus are characterized by their small, rod-shaped cells and a distinctive ability to metabolize a range of sulfur-containing compounds. Phylogenetic analysis based on 16S rRNA gene sequencing places Inhibbimus as a distinct lineage within the enterobacterial clade, with a basal divergence from the well-known genus Salmonella.

The type species, Inhibbimus sulfureus, was isolated from sediment samples collected in a sulfidic hot spring in Yellowstone National Park. The isolation procedure involved enrichment in a sulfur medium at 45 °C under strictly anaerobic conditions. Naming of the genus reflects the bacterium's characteristic inhibitory effect on competing sulfide-oxidizing microorganisms, as observed in co-culture assays. The authors of the original description proposed the name Inhibbimus to highlight the negative interference this organism exerts on nitrifying bacterial communities.

Morphologically, Inhibbimus cells exhibit a typical enterobacterial appearance with a single peritrichous flagellum. Genomic sequencing of the type strain revealed a 4.8 megabase genome with a GC content of 53%, containing genes for dissimilatory sulfite reductase and enzymes involved in both fermentative and respiratory pathways. Ecologically, strains of Inhibbimus have been detected in low-oxygen marine sediments, suggesting a role in sulfur cycling and potential influence on biogeochemical nitrogen transformations.

Research into Inhibbimus has implications for both basic microbial ecology and applied biotechnology. Its capacity to suppress nitrification in wastewater treatment systems could be harnessed to control nitrogen load, while its sulfur metabolism pathways present opportunities for bioaugmentation in the remediation of sulfidic mining effluents. Subsequent studies have begun to explore the regulatory mechanisms behind its inhibitory activity, positioning Inhibbimus as a promising model for investigating interspecies interactions in anaerobic environments.