磷酸盐和剪切力对螺旋霉素生物合成的影响

Effects of Phosphate Concentration and Sheer Stress on Spiramycin Biosyntheisi

文题试验结果表明，磷酸盐（Ｐｉ）过高固然有利于细胞生长，不利于螺旋霉素（ＳＰＭ）合成，但过低对生产也不好。发酵过程中补入适量Ｐｉ能显著提高细胞菌体的生产能力。根据静息细胞试验结果推测，Ｐｉ具有缓解过量葡萄糖或氨离子（ＮＨ）对ＳＰＭ合成的阻遏作用；能减少ＳＰＭ对其自身合成的反馈抑制，促进己糖和大环内酯的合成以及它们之间的连接。摇瓶发酵结果表明，单次补Ｐｉ的时间以发酵７２ｈ最有利，分二次补时以４２ｈ和８６ｈ最好，补入的Ｐｉ量以０．０５％～０．１％为宜。试验中还发现，ＳＰＭ发酵对剪切力很敏感，搅拌转达过高或摇瓶中加入玻璃珠会导致ＳＰＭ效价为零。

The effects of phosphate and sheer stress on spiramycin(SPM)biosynthesis were studied.The results showed that high concentration of phosphate(Pi)was favourable to growth while too low concentration of Pi would lead to reduction of SPM production. It was found that with suitable amount of phosphate supplement during the mid or late phase of fermentation,the productivity of SPM producing strains was greatly enhanced.According to the results of resting cell culture,the effect of Pi was suggested to alleviate the repression effect of high level of glucose or NH on SPM biosynthesis,and the feedback tepression of SPM as well.Pi was shown to pro-mote the biosynthesis of hexose and macrolactone as well as the linkage between them. The opti-mal time for Pi supplement were once at 72 h or twice at 42/86 h respectively. The optimal concentration of Pi used for supplement was 0.05%～0.1%,Sheer stress had profound effect on SPM biosvnthesis.