Development of Cordyceps militaris under different monochromatic lights

Light is an essential environmental factor for the stroma's production, accumulation of bioactive substances and pigmentation in Cordyceps militaris. In this study, different LED monochromatic lights (blue, green, red) were used for C. militaris cultivation. Effects of various monochromatic lights on bio-efficiency of stroma, biomass, and content of cordycepin were evaluated. Furthermore, expression of the Cmwc-1 gene in different light conditions was investigated.

The blue-light of 400 lux intensity highly affected stroma formation (16.97%). Red-light of 800 lux was the most optimal for biomass increasing (32.05g), then green-light of 800 lux (29.95g), blue-light of 400 lux (25.26g), darkness (13.89 g), and white-light (29.33g). Content of cordycepin obtained under 400 lux bluelight was 4329.77 μg/g, higher than that of 800 lux green-light (3364.00μg/g), 800 lux red-light (2797.77μg/g), white-light (2293.20μg/g) and darkness (1413.91μg/g). Cmwc-1 was hightly expressed in bluelight of 400 lux. Under dark condition, its expression was quite low. This result indicates that Cmwc-1 gene is a light-sensitive gene, particularly under blue light.

These results suggested a possibility of substitution of the white-light by monochromatic lights for increasing biomass and bioactive substance in C.militaris.