title: Isolation and Characterization of a Bacillus cereus Mutant Strain Hyperproductive of Exo-beta-Amylase.
abstract: Starting with a strain of Bacillus cereus excreting about 40-fold more beta-amylase than does the original wild-type strain, we isolated, after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine, a strain designated BQ10-S1 SpoIII which showed under optimal conditions a further 5.5-fold increase in beta-amylase activity. The amylase production of this strain was observed to increase in the presence of 0.5% glucose or 1% maltose and, more markedly, in the presence of 2% soluble starch in the culture medium. The enzyme produced by this strain was immunologically identical to the wild-type enzyme, suggesting that either the copy number of the gene or the efficiency of enzyme synthesis from it, or both, are altered in this strain.
authors.affiliation: Department of Agricultural Chemistry, Faculty of Agriculture, Kobe University, Rokkodai, Nada-ku, Kobe 657, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nanmori
authors.forename: Y
authors.initials: Y
authors.lastname: Numata
authors.forename: R
authors.initials: R
authors.lastname: Shinke