Authors: Huiling Wu Weicheng Liu Dan Dong Jinjin Li Dianpeng Zhang Caige Lu
Publish Date: 2013/10/31
Volume: 41, Issue: 1, Pages: 163-172
Abstract
Natamycin is an important polyene macrolide antifungal agent produced by several Streptomyces strains 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 natamycinpositive regulator slnM2 with different promoters in the newly isolated strain Streptomyces lydicus A02 which is capable of producing natamycin The slnM gene in S lydicus is highly similar to gene pimM scnRII the pathwayspecific positive regulator of natamycin biosynthesis in S natalensis and S chattanoogensis which are PASLuxR regulators Three engineered strains of S lydicus AM01 AM02 and AM03 were generated by inserting an additional copy of slnM2 with an ermEp promoter inserting an additional copy of slnM2 with dual promoters ermEp and its own promoter and inserting an additional copy of slnM2 with its own promoter respectively No obvious changes in growth were observed between the engineered and wildtype strains However natamycin production in the engineered strains was significantly enhanced by 24fold in strain AM01 30fold in strain AM02 and 19fold 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 of slnM2 Overall dual promoters displayed the highest transcription of biosynthetic genes and yield of natamycinThis work was supported by the Science and Technology Plan Project of Beijing no Z121100001212002 Special Research Fund for AgroScientific Research in the Public Interest from the Chinese Agriculture Ministry no 20090304907 and Science Research Innovation Fund from Institute of Plant and Environment Protection Beijing Academy of Agriculture and Forestry Sciences no CCJJZDXM2012012 The authors thank Dr Davide Spadaro Assistant Professor of DISAFA University of Torino for technical reading
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