Technique of Fine-Tuned Knockdown Using Samll Regulatory RNA and Its Application in Metabolic Engineering for Production of Putrescine from Escherichia coli

Abstract

Putrescine, 1,4-diaminobutane, is an important chemical which is used as a monomer of nylon in chemicalindustry. Biosynthesis of putrescine from renewable biomass is able to be a good substitute of petroleum basedputrescine production from an environmental point of view. There was a trial of development of putrescineproducing Escherichia coli strain through construction of biosynthesis pathway using gene knockout andoverexpression. We expected that productivity of this strain is able to be increased by use of recently developedknockdown method, small regulatory RNA system. Using this system we repressed competitive branch pathwaysand increased flux to putrescine. Additionally, culture condition was modified to support the increased putrescineproductivity by adding higher amount of nitrogen source and dissolved oxygen. The fed-batch cultivation offinally engineered strain and modified culture condition resulted in dramatically increase of productivity andyield. [This work was supported by the Technology Development Program to Solve Climate Changes on SystemsMetabolic Engineering for Biorefineries ; the Intelligent SyntheticBiology Center through the Global Frontier Project of the Ministry of Science, ICT and FuturePlanning (MSIP) through the National Research Foundation of Korea]