Growth Kinetics, Light Dynamics, and Lipid Production in Microalgae from Sugar-Mill Ponds

Sugar-mill wastewaters have potential to support microalgal biomass production for use as a biofuel feedstock (lipid source). Growth kinetics, light dynamics, and lipid production in multispecies-microalgae cultures collected from a sugar-mill pond are reported in this paper. Lipid content of the microalgae collected from the pond water was 14.5 % (w/w). Culturing the same microalgae in a photobioreactor on the pond wastewater supplemented with Gillard’s F/2 and CO2, and irradiated with 151 to 337 μmol s–1 m–2 artificial light produced cells with lipid contents of 11 % (w/w) at 25 °C, 35 % (w/w) at 31 °C, and 28.6 % (w/w) at 33 °C. The maximum specific growth rates (μmax) at 25 °C, 31 °C, and 33 °C were 0.64 d–1, 2.5 d–1, and 2.7 d–1, respectively. Under these conditions, cell densities as high as 1020 g cell dry mass (CDM) m–3 were recorded. Total scalar irradiance attenuation coefficient (k0) was 0.275 m –1 in clear water and 30.5 m–1 in the dense culture. The attenuation coefficient of irradiance due to biomass (kB) was found to be a linear function of cell concentration in this work.