Effect of low-frequency magnetic field on formation of pigments of Monascus purpureus

Monascus purpureus is a key fungus used to produce food pigments from secondary metabolites. Low-frequency magnetic field (LF-MF) affects production of M. purpureus secondary metabolites as one of the cultivation environments. The objective of this study was to measure optimum strength of induced magnetic field and duration of exposure for yellow and red pigment production of M. purpureus in solid-state fermentation. There was a 65.4 and 59.2 % increase in peak yield of yellow and red pigments compared to the control when the treatments were exposed to a magnetic field induction at 0.4 mT on the 8-9th day of incubation time. From kinetics of yellow and red pigment production, yield of yellow and red pigments was significantly increased in the samples exposed to magnetic field from the 8th to 11th day compared with that of the control group. LF-MF could increase the production rates of yellow pigments from 221.25 to 381.75 and red pigments from 165.00 to 292.50 U/g day. It could also significantly prolong the quickly generate time of yellow pigment. The appropriate magnetic field treatment could increase the efficiency of yellow and red pigment production.