Effect of different growth conditions on biomass yield and fucoxanthin content of Amphora capitellata

Abstract

The intention of the study was to investigate the effect of physical conditions such as aeration rate (1, 3, 5 L/min) as well as chemical conditions including sodium nitrite (NaNO2), urea (CH4N2O) and ammonium chloride (NH4Cl) on the biomass productivity and fucoxanthin concentration of A. capitellata. The optimum cultures were cultivated in f/2 medium using sodium nitrate (NaNO3) at the light intensity of 100 µmol photons/ m2s with aeration rate of 2 L/min in 2 L bubbling bottle photobioreactors. These were then incubated at 22.0±2 °C, under the light intensities of 300 µmol photons/ m2s with three different airflow rates of 1, 3, 5 L/min for 16 days. And then, culture medium was prepared with three different nitrogen sources to achieve higher biomass productivity. During the production of A. capitellata, the maximum specific growth rate of 0.166 day-1, which corresponded to the doubling time 4.166 day, was obtained at the light intensity of 300 µmol photons/ m2s with aeration rate of 1 L/min when sodium nitrate was used. Chlorophyll-a and fucoxanthin contents were also at the highest level in the same light intensity. Dry biomass amount reached the maximum level of 0.66±0.17 g/L in case of NaNO2. In this study, it was identified that the aeration rate of 1 L/min, the light intensity of 300 µmol photons/m2s and sodium nitrate (NaNO3) were the optimum value for the growth of A. capitellata cells and production of biomass and fucoxanthin concentration.