General Information: Isolation: Yellowstone National Park, acid hot; Country: USA; Temp: Thermophile; Temp: 60C. Alicyclobacillus acidocaldarius, formerly Bacillus acidocaldarius was first isolated from an acidic creek in Yellowston National Park and grows at a pH of 3.6. This organism is both thermophilic and acidophilic and produces heat and acid stable enzymes, such as amylase and esterase, which may be important in industry.