RESUMEN
In this study, a novel internally illuminated mirror photobioreactor (IIM-PBR) was designed to improve microalgae biomass production through providing a homogenous light distribution in cultivation medium. The performance of the IIM-PBR was compared with internally illuminated control photobioreactor (IIC-PBR) and externally illuminated control photobioreactor (EIC-PBR) in terms of cell growth, wastewater treatment and bioproducts generation. Compared with the IIC-PBR and EIC-PBR, the IIM-PBR increased microalgae growth rate up to 60 % and 30%, respectively. Municipal wastewater treatment revealed that the IIM-PBR could significantly improve nutrients removal as the final removal efficiencies of 90%, 95% and 90% were obtained for nitrate, phosphate and COD, respectively. Moreover, the IIM-PBR increased the total bioproducts production by 89% and 46% compared to in the IIC-PBR and EIC-PBR, respectively. Based on the energy consumption calculation, the mirror's light-reflective properties of the IIM-PBR resulted in a significant reduction of total energy consumption (â¼10 times).
Asunto(s)
Microalgas , Fotobiorreactores , Luz , Nitratos , Fosfatos , BiomasaRESUMEN
Microalgae cultivation is a promising approach to remove ambient CO2 via photosynthesis process. This paper investigates the impact of high CO2 concentrations (6, 12, and 16%) on algae growth, CO2 biofixation, lipid and carbohydrate contents, and nutrient removal of newly isolated microalgae, Coelastrum sp. SM. In addition, the ability of microalgae to produce biodiesel at optimal condition was studied. The microalgae were cultivated in wastewater using an airlift photobioreactor. Under 12% CO2, the maximum biomass productivity and CO2 fixation rate were 0.267 g L-1 day-1 and 0.302 g L-1 h-1, respectively. Total Kjeldahl nitrogen (TKN), total phosphorous (TP), nitrate, and sCOD removal efficiency were 84.01, 100, 86.811, and 73.084%, respectively. Under 12% CO2 and at the same condition for cell growth, the highest lipid and carbohydrate contents were 3 7.91 and 58.45%, respectively. The composition of fatty acids methyl ester (FAME) of the microalga lipid was defined. Based on the obtained results and FAME profile, Coelastrum sp. SM was a suitable feedstock for biodiesel production and also, the organism had a great potential for CO2 biofixation, which is also more suitable than any other reported strains in other related studies.
Asunto(s)
Biocombustibles/análisis , Dióxido de Carbono/metabolismo , Chlorophyceae/metabolismo , Microalgas/metabolismo , Biomasa , Metabolismo de los Hidratos de Carbono , Carbohidratos/química , Chlorophyceae/química , Chlorophyceae/crecimiento & desarrollo , Ácidos Grasos/química , Ácidos Grasos/metabolismo , Lípidos/química , Microalgas/química , Microalgas/crecimiento & desarrollo , Nitrógeno/análisis , Fósforo/análisis , Fósforo/metabolismo , Fotobiorreactores , Aguas Residuales/químicaRESUMEN
Cultivation of microalgae in wastewater is a promising and cost-effective approach for both CO2 biofixation and wastewater remediation. In this study, a new strain of Coelastrum sp. was isolated from cattle manure leachate. The isolated microalgae were then cultivated in wastewater. Effects of different sCOD concentrations (600, 750, 900, 1050 mg L-1) and light intensities (1000, 2300, 4600, 6900 and 10000 Lux) on biomass production, CO2 consumption rate and nutrient removal from wastewater were investigated. The results showed that maximum cell growth and CO2 consumption rate were 2.71 g L-1 and 53.12 mg L-1 day-1, respectively, which were obtained in the wastewater with 750 mg L-1 sCOD and under the light intensity of 6900 Lux. The microalgae were able to completely consume all CO2 after incubation period of 4 days. The highest sCOD, total Kjeldahl nitrogen (TKN), nitrate and total phosphorous (TP) removal at such conditions were 53.45, 91.18, 87.51 and 100%, respectively. The lipid content of microalgal biomass was also measured under different light intensities; maximum amount of lipid was determined to be 50.77% under illumination of 2300 Lux. Finally, the CO2 consumption rate and biomass productivity of microalgae in semi-batch culture with continuous gas flow (CO2 6%:N2 94%) were investigated. The rate of CO2 consumption and biomass productivity were 0.528 and 0.281 g L-1 day-1, respectively. The TKN, nitrate, TP and sCOD removal rate of microalgae were 83.51, 80.91, 100, 41.4%, respectively.