两性霉素B产生菌的诱变育种及发酵条件优化

摘要

In order to develop a robust producer of amphotericin B,streptomyces S.nodosus 150802 was used as the starting strain,and a robust producer of amphotericin B S.nodosus UV-13 was developed via UV mutagenesis.The fermentation conditions of S.nodosus UV-13 were further optimized by using one-factor-at-a time(OFAT)experiments.After subjected to UV irradiation for 60 s,a genetically stable,high-yielding mutant strain S.nodosus UV-13 was developed,which resulted in a 20％increase in amphotericin B titer compared with the parent strain S.nodosus 150802.The fermentation conditions of S.nodosus UV-13 were optimized.The maximal titer of amphotericin B reached 3.80 g/L under the optimized conditions,culture temperature 28 ℃,media loading size 50 mL per 250 mL,inoculation size 6％and fermentation time 7 d.%以结节链霉菌Streptomyces nodosus 150802为出发菌株,采用紫外诱变方法进行诱变选育出高产菌株S.nodosus UV-13,运用单因素实验设计方法优化了 S.nodosus UV-13发酵生产两性霉素B(AmB)的条件.实验结果表明:紫外诱变最佳照射时间为60 s,在此条件下,通过摇瓶初筛和复筛后选育出了一株稳定高产突变株 S.nodosus UV-13,其AmB发酵单位为2.46 g/L,较原始菌株提高了20.0％,经过传代5 代后仍表现出良好的遗传稳定性.单因素实验建立的最优 S.nodosus UV-13发酵条件:发酵温度28 ℃,摇瓶装液量每250 mL添加50 mL,接种量为6％,发酵周期7 d.在此最优发酵条件下,AmB发酵单位达到3.80 g/L.