Moorella

Moorella is a genus of thermophilic, Gram-positive, endospore-forming bacteria within the phylum Firmicutes. They are strictly anaerobic and are typically found in high-temperature environments such as hot springs, geothermal soils, and anaerobic digesters. Cells are rod-shaped and form endospores. Moorella species are predominantly acetogenic; they can obtain energy by fixing carbon dioxide into acetate via the Wood-Ljungdahl pathway, using hydrogen as an electron donor. In addition to autotrophic growth on H2 and CO2, several species can grow on organic substrates such as sugars and organic acids, often producing acetate as a primary metabolite.

Taxonomy and history: The genus Moorella was introduced to accommodate thermophilic, acetogenic bacteria that had previously been placed in Clostridium. Notably, Moorella thermoacetica was formerly described as Clostridium thermoaceticum; subsequent taxonomic rearrangements placed it in Moorella.

Notable species and significance: Notable members include Moorella thermoacetica and Moorella thermoautotrophica. The Wood-Ljungdahl pathway in Moorella makes it a subject of interest for studies on autotrophic carbon fixation and potential biotechnological applications in CO2 utilization and biofuel production. Research also investigates its role in anaerobic digestion processes and other environments where thermophilic acetogenesis occurs.