Rational Selection of Spiramycin-producing Strain
螺旋霉素产生菌的推理选育

The biosynthetic pathway of spiramycin were used for rational selection of spiramycin-producing strain. First, the L-valine-resistant mutant strains were selected, the productivity of the highest one of these strains increased 24%. Second the mutant strains resistant to a-aminobutyric acid were screened, the productivity of the highest one of these strains raised 26%. Finally, strain XC-533, whose genetics property of high productivity was stable, was gained by purification. The potency of the strain XC-533 had been increased 20% by production medium improvement. The fermentation of the new strain XC-533 was performed in 7m3 fermenter, and it made the potency and index of fermentation enhanced 73.19% and 32.14%, respectively.