Optimization of Chaetoceros gracilis microalgae production for fish feeding using an airlift photobioreactor

An experimental procedure was carried out to maximize Chaetoceros gracilis growth. Chaetoceros gracilis, marine microalgae, is considered for feeding fisheries with no GMO (Genetically Modified Organisms) to avoid human health hazards. Furthermore, following United Nations Resolution on water, the microalgae is grown in photobioreactors due to its low water usage. To maximize the microalgae growth, an experimental design was carried out to analyze the effects of Light Intensity, CO2 supply per day, Sparger type, Photoperiod and Inlet airflow, pH and water temperature were monitored but not controlled. It was found that Light intensity and CO2 supply per day have statistical significance. Out of three possible scenarios, 1700 lux and 80 gr/day of CO2, leads to a cell density at day three of 310×104 cel/mL which represents 20% more of the density attained in day two under bag (standard) growing conditions. It was also found that water Ph has also a strong effect over cell density.