代谢工程改造Bacillus amyloliquefaciens提高Surfactin产量

Metabolic Engineering of Bacillus Amyloliquefaciens to Improve Surfactin Production

Surfactin是芽孢杆菌属菌株通过多酶复合体合成的1种环状脂肽,属于次级代谢产物,具有异常优越的表面活性和抗菌、抗病毒、抗肿瘤等生物活性,但天然产量比较低.采用基因无痕操作方法,在Bacillus amyloliquefaciens NK-△LP菌株中敲除了2种结构类似物伊枯草菌素(Iturin)和丰原素(Fengycin)合成酶基因簇,构建了单敲菌株和双敲菌株;并分别过表达了与Swarming相关的SwrC蛋白、可能的跨膜转运蛋白YbfB和4'-磷酸泛酰巯基乙胺基转移酶Sfp,surfactin最高产量达50.17 mg/L,相对单位产量达38.59 mg/L;探究了相关代谢过程改造对菌株蜂群运动(Swarming)能力的影响,为surfactin工程菌株构建提供了参考.

Surfactin, which is one of the secondary metabolites synthesized by Bacillus sp. through multienzyme complex, turns out to be a cyclic lipopeptide with extremely superior surface activity as well as bioactivity of antibacterial, antivirus and anti-tumor, but with low natural yield. By applying a markerless gene replacement method to Bacillus amyloliquefaciens NK-△LP strain, two gene clusters that respectively encode analogues iturin and fengycin synthase were deleted to construct the recombinant strains of single knock-out and double knock-out. Owing to the overexpression of SwrC protein which is relevant to swarming, potential transmembrane protein YbfB and 4＇-phosphopantetheinyl transferase Sfp respectively,the highest yields of Surfactin was 50.17 mg/L, while the relative unit yield could reach to 38.59 mg/L.Besides, the effect of metabolic engineering on the ability of swarming of Bacillus sp. could have laid some solid foundation on relevant genetic engineering of Bacillus amyloliquefaciens.