摘要
目的通过基因工程定向改造尼莫克汀(nemadectin)产生菌蓝灰链霉菌(Streptomyces cyaneogriseus subsp.noncyanogenus),以阻断除主要杂质组分合成,提高有效组分产量。方法通过构建和筛选蓝灰链霉菌的基因组文库,获得了与LL-F28249ω合成相关的基因nolB。在蓝灰链霉菌的工业生产菌株NS1-8中连续删除尼莫克汀合成途径的nemD基因和类似寡霉素合成途径的nolB基因,获得了突变株NM-10。结果发酵检测产物表明,NM-10突变株产生活性组分LL-F28249α产量(1312mg/L)高于出发工业菌株NS1-8(1030mg/L),且不再产生LL-F28249γ、LL-F28249λ和LL-F28249ω等3个结构类似的杂质组份。结论 nemD和nolB基因连续敲除可用于改造产尼莫克汀蓝灰链霉菌工业产生菌,降低非有效组分含量并提高产量。
Objective To construct a nemadectin industrial strain with less byproducts by genetically engineering the Streptomyces cyaneogriseus subsp.noncyanogenus.Methods The nolB involved in LL-F28249ωbiosynthesis was cloned through screening the genomic library of Streptomyces cyaneogriseus subsp.noncyanogenus.Mutant strain NM-10 was obtained by sequential deletion of nolB and nemD involved in nemadectin biosynthsis from strain NS1-8.Results The nemadectin production of strain NM-10(1~312mg/L) was higher than that of strain NS1-8(1030mg/L).Furthermore there were no byproducts like LL-F28249γ,LL-F28249λ and LL-F28249ωcould be detected in strain NM-10.Conclusion Sequential deletion of nemD and nolB can be employed to improve production of nemadectin and decrease byproducts in S.cyaneogriseus subsp.noncyanogenus industrial strain.
引文
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