Production and fermentation optimization of nicotinamide mononucleotide by engineered Escherichia coli

• 1、 Biotechnology School, Jiangnan University, Wuxi 214122

Abstract：Nicotinamide mononucleotide (NMN) is a biologically active nucleotide, which plays an active role in improving body function, repairing sports injuries and delaying cell aging. In this study, Escherichia coli Z1 previously preserved in the laboratory was taken as the original strain. Through systematic metabolic modification of strain Z1: weakening the competition pathway, weakening the degradation pathway of products and increasing the transformation of substrate glucose, an engineering strain Z5 which can effectively biosynthesize NMN was successfully obtained, and its NMN production was 252.2 mg/L. On the basis of single factor experiment, Box-Behnken method was used to design and optimize the fermentation medium components of strain Z5. Under the optimal conditions, the NMN production was 265.4 mg/L, which was 75.1% higher than that of the original strain. Then, the optimum culture conditions were as follows: pH 7.5, inoculation amount 4%, shaking speed 150 r/min. After fed-batch fermentation in a 5 L fermentor, the strain Z5 produced NMN 4.21 g/L in 24 hours, and the nicotinamide conversion rate was 48.7%. Therefore, the production of NMN was effectively improved by metabolic engineering and optimization of fermentation conditions, which provided certain reference value for large-scale production of NMN.

Keywords： Nicotinamide mononucleotide Escherichia coli Metabolic engineering fermentation optimization