Which bacterial species produces the enzyme Taq polymerase used in PCR?

Thermus aquaticus produces the heat-resistant Taq polymerase used in PCR.

This bacterium is a thermophile first isolated in 1966 from Mushroom Spring in Yellowstone National Park; Thomas Brock and Hudson Freeze formally described it in 1969. Its enzymes remain functional at temperatures that would destroy proteins from ordinary bacteria.

Taq polymerase was isolated in 1976. PCR repeatedly heats DNA to about 95°C to separate its strands, so a heat-stable polymerase can copy DNA through many cycles without being replaced. Before Taq became standard, researchers often used Escherichia coli polymerase, which had to be replenished after heating.

A common mix-up is Pyrococcus furiosus: it supplies another thermostable polymerase, Pfu, valued for higher copying accuracy, but Taq is the classic PCR enzyme named after T. aquaticus. The name “Taq” combines the genus abbreviation with the species initial.