Effects on the sporulation and secondary metabolism yields of Monascus purpureus with mokH gene deletion and overexpression

Abstract

Monacolin K is a secondary metabolite of Monascus and is known to decrease cholesterol levels in humans. There are 9 genes (mokA-mokI) controlling its biosynthesis, of which mokH is thought to act as a pathway-specific regulator. In this study, the Monascus purpureus M1 strain was compared with mokH gene deletion strains (△H1) and overexpression strains (H7). The monacolin K yields in the △H1 strain were reduced by 52.05 %, and increased in the H7 strain by 82 %. The mycelium samples of the M1, △H1, and H7 strains were found to vary with scanning electron microscopy. Compared to the M1 strain, some mycelium of the △H1 strain showed obvious folding and expansion, while the mycelium of the H7 strain was fuller. Besides, these results indicate that the mokH gene can increase the yield of monacolin K by regulating the expression level of mokA-mokI genes, and influence the production of Monascus pigment. The study is the first to combine deletion and overexpression techniques to further verify the mokH gene and get the desired results in M. purpureus.