Amylase production by three Bacillus strains active at alkaline pH

Thermostable α‐amylases produced by three different strains of Bacillus species are reported. The organisms are isolated from soil. They are designated as Bacillus stearothermophilus A004, B. stearothermophilus AN002 and B. coagulans R3. The heat stable amylases produced by these organisms were partially purified and characterized. The temperature optimum for B. stearothermophilus A004 and B. stearothermophilus AN002 amylase is 80 °C, whereas the optimum temperature for amylase activity is 85 °C for B. coagulans R3. The amylases from all three strains show extremely broad pH ranges of activity (6.0–12.0). Furthermore, the α‐amylases from B. coagulans R3 retains 35% activity even at 0.1 n alkali solution. Action of these enzymes on starch produces glucose, maltose, maltotriose, maltotetrose and other higher oligosaccharides, indicating the α‐amylase nature of the three enzymes.