smithella propionica smithella propionica smithella propionica is a species of bacteria, the type species of its genus. it is anaerobic, syntrophic, propionate-oxidizing bacteria, with type strain lypt (= ocm 661t). smithella propionica scientific classification domain: bacteria phylum: thermodesulfobacteriota class: syntrophia order: syntrophales family: syntrophaceae genus: smithella species: s. propionica binomial name smithella propionicaliu et al. 1999