Selection For High-Yield Alkaline Chitinase-Producing Strain By Protoplasttechnique

Streptomyces griseofuscus ( SI001) has the ability to produce alkaline-chitinase.This thesis is divided into two parts: I )cultural condition for forming and stabilizing protoplasts of Streptomyces griseofuscus were studied by reference to the number of protoplasts formed ,leakage from protoplasts and reversion rate.Hypha in logarithmic phase(41hr) is the best material for making portoplast; Gly has no assisstance in taking off the cell wall;The best condition for making protoplast:the concentration of Lysozyme of 1 Omg/ml -, 1 hn 25 "C ;Effective formation and stabilization of the protoplasts was accomplished by using a hypertonic medium containing 25mM MgCl2and lOmM CaCl2. II )After treating the protoplasts of S1001 with UV> MNNG,the mutant strain M13 were obtained .It's enzyme activity get improved better 6 times than starting strain, reaching 15.2U/ml .This study also shows that compared with the check,the protoplast technique has the advantage of high mutation rate and large improvement range .It is a simple, practical and effective technique for mutating strain.