Improvement of carbon dioxide removal through artificial light intensity and temperature by constructed green microalgae consortium in a vertical bubble column photobioreactor

Abstract

Aims: This study was aimed to demonstrate that environmental conditions, such as light intensity, photoperiodism and temperature, played a determining role in improving CO2 removal and cellular propagation. Photosynthesis by microalgae in a direct CO2 to biomass conversion in engineered systems such as photobioreactors, has been frequently used for CO2 removal. The goal of this study was to obtain high CO2 removal by green microalgae strains cultivated in a vertical bubble column photobioreactor. Methodology and results: Constructed consortium containing Chlorella sp., Scenedesmus obliquus, and Ankistrodesmus sp. were cultured in temperatures (°C) of 25, 30, 25; light intensities (lux) of 2500, 4000 and photoperiodisms (light/dark; hour) of 24/0, 16/8, and 12/12. The experiment demonstrated that microalgae was capable of tolerating up to 7% CO2 concentrations under variation of light intensities, photoperiodisms, and temperature conditions. Synergetic of three microalgae capable of utilizing CO2 and transformed it to become biomass. The result also showed that growth was best at light intensity of 4000 lux for 16 h a day and temperature of 30 °C. The maximum growth rate (µ) of 0.38 per day was obtained from culture injected with 5% CO2 concentration. Conclusion, significance and impact study: The CO2 removal efficiency (%) was 49.02, whereas CO2 utilization efficiency (%), carbon dioxide transfer rate (CTR; gCO2/L.h) and carbon dioxide fixation rate (qCO2/h) were 15.15, 101.29 and 42.02, respectively. Biofixation of CO2 by the constructed consortium has recently gained renewed interest as a promising strategy for CO2 mitigation.