thermoanaerobacter brockii thermoanaerobacter brockii thermoanaerobacter brockii, formerly thermoanaerobium brockii, is a thermophilic, anaerobic, spore-forming bacterium. thermoanaerobacter brockii scientific classification domain: bacteria phylum: bacillota class: clostridia order: thermoanaerobacterales family: thermoanaerobacteraceae genus: thermoanaerobacter species: t. brockii binomial name thermoanaerobacter brockii(zeikus et al. 1983) lee et al. 1993 the bacterium was first isolated from yellowstone national park. the growth range for the organism is 35 to 80°c and ph 5.5-9.5, with optimal growth conditions at 65-70°c and ph 7.5. t. brockii stains gram-positive. while originally thought to be non-sporeforming bacteria, it was later discovered that the organism produced spores that can survive heating at 115 °c for 80 min. the species was originally classified as thermoanaerobium brockii, but further analysis put the bacteria into the genus thermoanaerobacter. the species is named "in honor of t.d. brock, a pioneer in the golden era of thermophily."