为提高米尔贝霉素发酵效价及发酵稳定性，对米尔贝霉素产生菌的种子培养工艺和移种标准进行了研究。结果表明，一级种子培养的较佳条件为：接孢量为3%（斜面孢子生长8 d，孢子悬液浓度为1×108~7×108 个/mL），28 ℃培养41 h。可适用于菌株的分离纯化及摇瓶发酵的种子液制备。同时，为了更好地与发酵罐的放大研究相衔接，采用二级种子培养的较佳工艺条件为：一级种子培养30 h 后，接入二级种子培养基，培养43 h，此时种子液pH 值约7.2，菌浓约29%~33%，总糖含量20 g/L，氨基氮含量292 mg/L，与一级种子的生长状况和生产水平相比，种子液菌浓和米尔贝霉素产量分别提高了4%和5.6%。

In order to improve milbemycin productivity and fermentation stability, the cultivation process and inoculation standard of milbemycin-producing strain were studied. The results showed that the optimal primary seed culture conditions were as follows: inoculation volume 3% (spores culture time 8 d, spore suspension concentration 1×108-7×108 spores/mL), grown 41 h under 28 ℃. For scale-up, the primary seed after 30 h cultivation was inoculated into the medium of secondary seed and cultivated for another 43 h. The characteristics of the secondary seed culture were as follows: pH value 7.2, mycelium concentration 29%-33%, total sugar content 20 g/L and amino nitrogen content 292 mg/L. The mycelium concentration and the productivity were increased by 4% and 5.6% compared with the primary seed cultivation, respectively.