Effects of light-emitting diodes under capped daily energy consumption with combinations of electric power and photoperiod on cultivation of Chlorella pyrenoidosa

• Highest growth rate and efficiency were obtained at different light intensities.
• Growth efficiency and growth rate were simultaneously improved by a novel method.
• The order of them under different LEDs were white > blue > red.
• The generation of chlorophyll was more sensitive to light combinations under blue.

Effects of white light-emitting diodes (LEDs) with different light intensities at photoperiod of 18:6 h on Chlorella pyrenoidosa growth were investigated. The microalgae exhibited the highest growth rate 89.0 mg L−1 d−1 and growth efficiency 97.8 mg L−1 KWh−1 at 110 and 90 μmol m−2 s−1, respectively. Based on the discovery of this asynchronous phenomenon between growth rate and growth efficiency, influences of LEDs (red, blue and white) under capped daily energy consumption (0.80 KWh d−1) with combinations of electric power (33.3, 44.4 and 66.6 w) and photoperiod (24:0, 18:6 and 12:12 h) were further investigated. The highest growth efficiency 106.4 mg L−1 KWh−1 and growth rate 85.1 mg L−1 d−1 were both obtained under white-33.3 w-24 h. Growth efficiency and growth rate were simultaneously improved 1.1 times through this method above. The order of growth efficiency under different LEDs were white > blue > red.