SlnM gene overexpression with different promoters on natamycin production in Streptomyces lydicus A02

发布时间：2016年09月27日 14:08　　浏览次数：1164

Huiling Wu ·Weicheng Liu·Dan Dong et al.

J Ind Microbiol Biotechnol (2014) 41:163–172

DOI 10.1007/s10295-013-1370-7

Natamycin is an important polyene macrolide antifungal agent produced by severalStreptomycesstrains and is widely used as a food preservative and fungicide in food, medicinal and veterinary products. In order to increase the yield of natamycin, this study aimed at clon­ing and overexpressing a natamycin-positive regulator,slnM2, with different promoters in the newly isolated strainStreptomyces lydicusA02, which is capable of producing natamycin. TheslnMgene inS.lydicusis highly similar to genepimM(scnRII), the pathway-specific positive regula­tor of natamycin biosynthesis inS.natalensisandS.chat­tanoogensis, which are PAS-LuxR regulators. Three engi­neered strains ofS.lydicus, AM01, AM02 and AM03, were generated by inserting an additional copy ofslnM2with an ermEp* promoter, inserting an additional copy ofslnM2with dual promoters, ermEp* and its own promoter, and inserting an additional copy ofslnM2with its own pro­moter, respectively. No obvious changes in growth were observed between the engineered and wild-type strains. However, natamycin production in the engineered strains was significantly enhanced, by 2.4-fold in strain AM01, 3.0-fold in strain AM02 and 1.9-fold in strain AM03 when compared to the strain A02 in YEME medium without sucrose. These results indicated that the ermEp* promoter was more active than the native promoter ofslnM2. Over­all, dual promoters displayed the highest transcription of biosynthetic genes and yield of natamycin.