[Cofactor engineering strategy for enhanced S-adenosylmethionine production in Saccharomyces cerevisiae]

In order to study the role of cofactor engineering in enhancing the production of S-adenosylmethionine (SAM), we altered the form and concentration of cofactor in Saccharomyces cerevisiae through gene recombination. Effects of cofactor on product synthesis, carbon and energy metabolism were analyzed aiming to provide a theoretical basis for a successful metabolic engineering of SAM producing strains. Because NADPH metabolism in mitochondrion and cytoplasm of S. cerevisiae is relatively independent, the effect of intracellular NADPH availability on the production of SAM was studied in different compartments of S. cerevisiae BY4741. The expression of NADH kinase in mitochondria (POS5 encoded) and cytoplasm (POS5Δ17 encoded) was separately confirmed using a laser scanning confocal microscope. NADPH regulation strategy enhanced SAM production. Compared with the control strain, the intracellular SAM concentration of strain NBYSM-1 was increased by 3.28 times, and the intracellular SAM concentration of strain NBYSM-2 was increased by 1.79 times at 24 h fermentation. In addition, SAM titer and NADPH/NADP⁺ ratio in strain NBYSM-1 were significantly higher than that of strain NBYSM-2. Therefore, NADPH regulation strategy will be a valuable tool for SAM production and could further improve the synthesis of a large range of cofactor-driven chemicals.