thermotoga lettingae thermotoga lettingae thermotoga lettingae is a thermophilic, anaerobic, non-spore-forming, motile and gram-negative bacterium, with type strain tmot. thermotoga lettingae scientific classification domain: bacteria phylum: thermotogota class: thermotogae order: thermotogales family: thermotogaceae genus: thermotoga species: t. lettingae binomial name thermotoga lettingaebalk et al. 2002