The effects of different light intensity and wavelength on growth and biomass of microalgae Nannochloropsis oculata

Abstract

In the present study, the effect of three light wavelengths including blue, red, and white light and three light intensities (1000, 2000, 3000 LUX) were investigated on the growth rate, duplication time, and biomass production in microalgae Nannochloropsis oculata. Different treatments of algal cultures were cultured under 25 ppt salinity at temperature 24 ºC, and photoperiod cycle 12:12 (light:dark) using Guillard medium. The whole period of this experiment was 12 days. Cell count was conducted every other day and the biomass was measured on the last day in different treatments. The highest cell concentration (33×106 cell ml-1) was obtained in treatment with blue light and 2000 LUX after 10 days of culture. The maximum specific growth rate (0.40±0.01 d-1) was observed at the blue light and 3000 LUX and also the minimum duplication time occurred at this treatment (1.16±0.03 d-1). The maximum biomass (0.54± 0.003 gl-1) was recorded at the blue light and 2000 LUX. According to the results, the best light condition for adaptation of microalga N. oculata to cultural systems and obtaining maximum cell concentration and biomass is blue light with 2000-3000 LUX light intensity. Therefore, this light regime is recommended for N. oculata culture in phycolabs and aquaculture systems.

Keywords

• light wavelength
• microalgae
• biomass
• nannochloropsis