Thermostable cyclodextrin glycosyl transferase and processes using it

Abstract

Novel cyclodextrin glycosyl transferases (CGTase) can be produced by anaerobic cultivation of strains of Thermoanaerobacter or Thermoanaerobium. They are more thermostable than known CGTases and have temperature optimum about 95° C. The novel CGTases can be used for starch liquefaction at pH 4.5 and temperature exceeding 100° C. in the production of dextrose or ethanol. They can also be used for conversion of liquefied starch to cyclodextrin at a temperature of 80-90° C. A method for enzymatically converting solid and liquefied starch into cyclodextrin using cyclodextrin glycosyl transferases (CGTase) elaborated by thermophilic obligate anaerobic strains belonging to the genus Clostridium. These CGTases are characterized by thermostability and a capability to liquefy starch and/or to convert liquefied starch to cyclodextrin at pH 5.0-5.5 and 60-90° C.

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