Influence of Light and Temperature on Secondary Metabolites Production by Monascus Ruber in Rice Solid Cultures

Abstract

Monascus species have been used in Chinese fermented foods such as Anka pork, and rice wine because of its bioactive substances including pigment, and monacolin K. In this study, the effect of light and temperature on red pigment, total polyphenols, DPPH radical scavenging, reducing ability and monacolin K of Monascus ruber BCRC31535 in rice solid culture was conducted. No obvious difference was observed by the DPPH radical scavenging assay whatever the cultural condition of light and temperature was performed. However, the results revealed that the red pigment, total polyphenols, reducing ability and monacolin K were the highest in the darkness at 30°C. Blue light and red light remarkably declined these secondary metabolites and antioxidant capacity, probably resulting from the induction of oxidative stress. By contrast, blue light can stimulate the production of red pigment and monacolin K at 20°C while red light can improve the reducing ability. Nevertheless, total polyphenols were not affected by light at the low temperature. Taking together, the temperature was also the interference factor in the solid-state culture of M. ruber BCRC31535, which influenced the light on the yield of secondary metabolites.