Screening and UV Mutagenesis of Protease Producing Strains

Objective:To obtain high and well defined protease-producing strains.These strains can be used in seafood process to produce poly-peptide.Method:The protease-producing strains were first screen from soil by well-designed sampling sites and colony screening,fermentation supernatant identification and Folin-phenol measurement assay etc.To improve the production of protease capability for the target strain,UV mutagenesis were further introduced.Result:187 protease-production strains were screened from the collected 12 soil samples.Further secondary screening indicated a strain W9 produced stably higher enzyme activity than any other strains among the primary screened 11 strains.The activity of strain W9 reached to 1 594U/ml.Mutant strain W9UV was obtained by UV mutagenesis which enhances the protease activity by 15.6% in comparison with that of the wild strain W9,with the activity of 1845 U/ml.Conclusion:W9UV strain has a greater protease activity and more stably fermentation performance.