Most living organisms cannot survive at temperature above 45°C

Most living organisms cannot survive at temperature above 45°C. How are some microbes able to live in habitats with temperature exceeding 100°C?

In most animals, the metabolic reactions occur in a narrow range of temperature, e.g. human at 37°C. Above this temperature, enzymes get denatured. The microbes live in habitats with temperatures exceeding 100°C, because they are adapted to such temperatures and they have heat tolerant enzymes.