2005•Food ScienceRequires access
Screening High-yield Nattokinase Producing Strain by Protoplast Mutagenagsis with UV
Mingsheng Dong
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Abstract
Taking Bacillus subtilis natto B.N.K as initial strain, under the optimum conditions of formation and regeneration, the protoplast of the strain was prepared. The regenerative mutants from the protoplasts with UV mutagenic treatment were screened for strains of high nattokinase activity. After repetition of UV mutation, screening and gene stability assay of mutants, five strains, DU115, DU120, DU212 and DU223 were finally obtained. Their enzyme activity were 383.65, 400.74, 327.15, 347.16, 378.98 IU/ml respectively, separately increased by 67.1%, 74.5%, 42.5%, 51.2% and 65.0% respectively.