Light is an important factor for cordycepin production in Cordyceps militaris. We investigated the effects of different light-emitting diode (LED) conditions including various LED wavelengths and their combinations on cordycepin production in Cordyceps militaris cultivated in submerged culture. The results of our study showed that the combinations of LED wavelengths were more beneficial than single LED sources for cordycepin production. Among the three tested wavelength combinations, the greatest effects for cordycepin production were observed for the red:blue light combination at the wavelength ratio of 5:5 or 3:7. The optimal culture conditions were 19.2278 h/day of illumination time; 9.19497 g/50 mL of glucose content in the media; and 53.112 h of cultivation time. Our model predicted a maximum yield of 2860.01 μg/mL cordycepin. Finally, to verify the calculated maximum, we performed experiments in the culture media representing the obtained optimum combination and the cordycepin yield of 2412.5 μg/mL.

ABSTRACT
NTRODUCTION
MATERIALS AND METHODS
    Reagents and standards
    Mycelia preparation
    Submerged culture
    Different wavelengths of LEDs
    Combination of different ratios of wavelength ofLEDs
    Illumination time
    Glucose content in media
    Determination of mycelia dry weight
    Determination of cordycepin
    Experimental design by RSM
RESULTS AND DISCUSSION
    Effect of various media on mycelia dry weight andproduction of cordycepin
    Effect of LEDs on mycelia dry weight andcordycepin content
    Influence of light illumination time on mycelial dryweight and cordycepin contents
    Effects of LEDs combination on the mycelia dryweight and cordycepin content
    Optimization of cordycepin production by RSM(BBD)
REFERENCES

• Si-Young Ha(Division of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University)
• Ji-Young Jung(Division of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University)
• Jai-Hyun Park(Division of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University)
• Dong-Hwan Lee(Division of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University)
• Ji-Won Choi(Division of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University)
• Jae-Kyung Yang(Division of Environmental Forest Science/Institute of Agriculture and Life Science, Gyeongsang National University) Corresponding author