Abstract:Monascus fermentation can produce various beneficial secondary metabolites, such as Monacolin K, Monascus pigments, and so on. Monacolin K can inhibit cholesterol synthesis and reduce blood lipid levels. However, wild-type Monascus strains have extremely low yields of Monacolin K, significantly limiting the application of functional Monascus products. The previous metabolomics analysis of the author’s research team revealed that the tricarboxylic acid cycle (TAC) is involved in regulating Monacolin K synthesis, and fumaric acid expression was positively correlated with the synthesis of Monacolin K. To further investigate the effect of fumaric acid on the growth and secondary metabolism of Monascus purpureus and to improve Monacolin K yield in Monascus purpureus, the author utilized the wild-type strain Monascus purpureus M1 as the fermentation strain. Using methods such as dry weight measurement, spectrophotometry, scanning electron microscopy, ultra-high-performance liquid chromatography, and real-time quantitative PCR, this author investigated the impact of fumaric acid addition on Monascus growth and the synthesis of secondary metabolite Monacolin K, as well as the yellow, orange, and red pigments of Monascus. The results demonstrated that fumaric acid addition inhibited the growth of mycelia and the synthesis of Monascus pigments. However, it increased the degree of mycelial folding and density, with Monacolin K production showing a 49.38% increase compared to the control. Additionally, nine genes associated with Monacolin K synthesis exhibited varying degrees of upregulation.
