Extremely low-frequency magnetic fields affect pigment production of Monascus purpureus in liquid-state fermentation

Abstract

Red pigment is one of natural coloring agents produced from the secondary metabolites of Monascus purpureus. Measures are taken to increase the pigment production. Effect of the extremely low-frequency magnetic field on the red and yellow pigment production of M. purpureus in liquid-state fermentation was estimated by exposing fermentation broth, medium and sterile distilled water used to prepare medium. The maximum yield of red and yellow pigment production had about 20 and 36 % increase for 8 days at 0.4 mT when treating fermentation broth compared to the control value. For sterile distilled water, a significant increase occurred at 0.4 mT compared to 0.1 mT for 5 h. However, the red and yellow pigment production decreased significantly at magnetic fields of 0.9 and 1.2 mT when treating fermentation broth and sterile distilled water. In contrast, the yield of both red and yellow pigment production decreased significantly compared with the control exposure for 3 and 5 h at a magnetic field of 0.4 mT. Different solution (cellular suspension, medium and sterile distilled water) exposure to magnetic fields has different bioeffect on M. purpureus SKY219. The appropriate magnetic field treatment could increase the efficiency of red and yellow pigment production.