Effect of blue light on the growth, culture morphology, and pigment production of monascus

Blue light is an environmental signal that can regulate most organisms, including the physiological processes of fungi. In this paper, the effects of blue light on the culture morphology, spore formation, and red pigment production of Monascus were investigated. Blue light restricted the formation of aerial hyphae, affected the colony morphology, delayed and increased the formation of conidia, reduced asci, and initiated the sexual cycle at the early stages of growth. It also reduced red pigment production in aerial hyphae and spores. However, 12 d of blue light exposure did not affect red pigment production in culture medium and total pigment production. These findings suggest that Monascus can sense blue light through photoreceptors and respond by modifying colony morphology, changing spore formation, and decreasing red pigment production in aerial hyphae.