Increase in thermostability of recombinant barley beta-amylase by random mutagenesis

Random mutations were introduced into recombinant barley beta-amylase by modified PCR to increase its thermostability. Two clones were obtained. One was found to have a change of Ser-351 to Pro and another, a change of Ala-376 to Ser, and 2.3 degrees C and 1.0 degrees C increases, respectively, in the thermostabilities compared with that of native recombinant beta-amylase.