The influence of photoperiod, light intensity, temperature and salinity on the growth rate and biomass productivity of Botryococcus sp

Abstract

Environmental factors such as photoperiod, light intensity, temperature, and salinity strongly influence the growth rate and biomass accumulation of microalgae in a culture. Therefore, the effects of photoperiod (24h light: 0h dark, 16h light: 8h dark, 12h light: 12h dark, 6h light: 18h dark and 0h light: 24h dark), light intensity (2.7, 48.6, 94.5, 176, 243 and 324 μmole m−2s−1), temperature (18, 23, 28, 33 and 38 °C), and salinity (0, 0.15, 0.3, 0.45, 0.6 M of NaCl) factors on the growth rate and biomass productivity were studied for green microalgae, Botryococcus sp. Botryococcus sp. was found to experience optimum growth with a photoperiod of 24:0 hours, light intensity of 243 μmol m−2s−1, temperature of 23 °C, and 0 M salinity. It was also observed that optimum biomass productivity of Botryococcus sp. was the same as that for growth rate optimum environmental factors. However, a temperature of 33 °C was shown to be optimum for biomass productivity. Freshwater green microalgae from genus Botryococcus sp. were examined for environmental factors in this study and show great potential for adoption in tropical climates such as Malaysia for the bio-based feedstock and biofuels industries.