Which bacterium supplies the heat-stable Taq polymerase used in PCR?

Thermus aquaticus supplies the heat-stable Taq polymerase used in PCR.

Thermus aquaticus is a thermophilic bacterium first isolated from a hot spring in Yellowstone National Park. Its enzymes function at temperatures that would denature proteins from many ordinary bacteria. The best-known enzyme is Taq polymerase, a DNA-copying enzyme used in the polymerase chain reaction.

PCR repeatedly heats DNA to separate its strands and then cools it so primers can guide copying. Before a thermostable polymerase was available, researchers had to add fresh enzyme after each heating step. Taq polymerase made automated cycling practical and helped PCR become a standard method in research, medicine, forensics, and diagnostics.

Taq is named from the first letter of Thermus and the species name aquaticus. Thermotoga maritima is another heat-loving bacterium with useful enzymes, but it is not the source of the canonical Taq polymerase. PCR copies selected DNA sequences; it does not itself identify every organism without suitable primers and analysis.