螺旋霉素产生菌的推理选育

Rational Selection of Spiramycin-producing Strain

螺旋霉素(Spiramycin,以下简称SPM)为十六元大环内酯类抗生素。内酯环C-3位上羟基酰化侧链片段构成SPM不同组分。C-3位上羟基酰化酶的合成受葡萄糖的诱导,该诱导作用受丁酸的抑制。SPM的生物合成受高浓度铵离子的抑制。而支链氨基酸,如缬氨酸,经分解代谢可产生乙酸、丙酸、丁酸,作为SPM生物合成的前体。本文根据SPM的生物合成途径,采用诱变和耐L-缬氨酸、耐a-氨基丁酸相结合的筛选方法,获得了高产菌株.

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.