Evaluation of the Effects of the Blinking Cycle and Duty Ratio of Red and Blue Light Emitting Diodes on the Photosynthetic Rate of Euglena

This study is designed to clarify the optimum optical irradiation conditions for efficient cultivation and increased crop yields of Euglena gracilis. Specifically, we studied the light conditions (light blinking cycle, blinking light duty ratio, light quantity, etc.) to determine the optimum values for promoting efficient light usage for photosynthesis (energy efficiency) by measuring the photosynthesis rate while irradiating Euglena with light emitting diode (LED) blinking light. We determined that the light conditions listed below produce the highest “Light energy usage efficiency.” (1) Set the blinking cycle of the LED blinking light to the “Optimum cycle area.” (2) If the blinking cycle is set to a short period (e.g.: below 1.0×10 s), the recommended range for the blinking duty ratio is 10-100%.