Hyperthermostable alpha-amylase

摘要

PCT No. PCT/DK90/00074 Sec. 371 Date Aug. 22, 1991 Sec. 102(e) Date Aug. 22, 1991 PCT Filed Mar. 19, 1990 PCT Pub. No. WO90/11352 PCT Pub. Date Oct. 4, 1990.A hyperthermostable alpha-amylase is provided by culturing strains of Pyococcus. These enzymes are of great interest for industrial applications, for example in starch liquefaction processes. The microorganisms Pyococcus woesei or Pyococcus furiosus are capable of producing the desired alpha-amylase with the following properties: (a) a pH optimum between 4.0 and 6.0; (b) a temperature optimum between 80 and 120 degrees centigrade; (c) an activity which is essentially independent of calcium ions; and (d) a residual activity of 100% after one hour at 90 degrees centigrade and of at least 80% after one hour at 100 degrees centigrade in the presence of stabilizing amounts of substrate.