Genetic engineering strain of high-yield beta-nicotinamide mononucleotide as well as construction and application thereof

The invention discloses a genetic engineering strain for high yield of beta-nicotinamide mononucleotide. The genetic engineering strain is constructed by the following steps: overexpressing any one, two or three of NAD + synthetase gene NadE, nicotinic acid phosphoribose transferase gene PncB and transporter gene PnuC; the genetically engineered bacterium is obtained by taking bacillus subtilis or escherichia coli or yeast as a chassis strain and at least over-expressing one gene of NAD + synthetase NadE, nicotinic acid phosphoribosyltransferase PncB and transporter PnuC in the chassis strain, so that high yield of beta-nicotinamide mononucleotide through microbial fermentation is realized. Expensive raw materials such as ATP and nicotinamide do not need to be used, and the economic benefit is remarkable. 本发明公开了一种高产β-烟酰胺单核苷酸的基因工程菌株，构建步骤如下：过表达NAD+合成酶基因NadE、烟酸磷酸核糖转移酶基因PncB和转运蛋白基因PnuC三种基因中的任意一个或两个或三个。本发明基因工程菌是以枯草芽孢杆菌或大肠杆菌或酵母为底盘菌株，在底盘菌株中至少过表达NAD+合成酶NadE、烟酸磷酸核糖基转移酶PncB与转运蛋白PnuC其中的一个基因获得的，从而实现微生物发酵高产β-烟酰胺单核苷酸。本发明无需