米尔贝霉素产生菌种子培养工艺及移种标准的研究

Seed cultivation process and inoculation standard of milbemycin-producing strain

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/m L）,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p H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 1×10^8-7×10^8 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 ni- trogen content 292 mg/L. The mycelium concentration and the productivity were increased by 4% and 5.6% compared with the primary seed cultivation, respectively.