Algal Consortium Research Articles

An evaluation of autotrophic microbes for the removal of carbon dioxide from combustion gas streams

Carbon dioxide is a greenhouse gas that is believed to be a major contributor to global warming. Studies have shown that significant amounts of CO 2 are released into the atmosphere as a result of fossil fuels combustion. Therefore, considerable interest exists in effective and economical technologies for the removal of CO 2 from fossil fuel combustion gas streams. This work evaluated the use of autotrophic microbes for the removal of CO 2 from coal fired power plant combustion gas streams. The CO 2 removal rates of the following autotrophic microbes were determined: Chlorella pyrenoidosa, Euglena gracilis, Thiobacillus ferrooxidans, Aphanocapsa delicatissima, Isochrysis galbana, Phaodactylum tricornutum, Navicula tripunctata schizonemoids, Gomphonema parvulum, Surirella ovata ovata, and four algal consortia. Of those tested, Chlorella pyrenoidosa exhibited the highest removal rate with 2.6 g CO 2 per day per g dry weight of biomass being removed under optimized conditions. Extrapolation of these data indicated that to remove CO 2 from the combustion gases of a coal fired power plant burning 2.4 × 10 4 metric tons of coal per day would require a bioreactor 386 km 2 × 1 m deep and would result in the production of 2.13 × 10 5 metric tons (wet weight) of biomass per day. Based on these calculations, it was concluded that autotrophic CO 2 removal would not be feasible at most locations, and as a result, alternate technologies for CO 2 removal should be explored.

Bioluminescent dinoflagellates : Sweeney, B. M., 1963, Biol. Bull, 125 (1): 177–181

The microalgal biomass applications strongly depend on cell composition and the production of low cost products such as biofuels appears to be economically convenient only in conjunction with wastewater treatment. As a preliminary study, in view of the development of a wastewater treatment pilot plant for nutrient removal and algal biomass production, a biological wastewater system was carried out on a laboratory scale growing a newly isolated freshwater algal strain, Desmodesmus communis, and a natural consortium of microalgae in effluents generated by a local wastewater reclamation facility. Batch cultures were operated by using D. communis under different growth conditions to better understand the effects of CO2, nutrient concentration and light intensity on the biomass productivity and biochemical composition. The results were compared with those obtained using a natural algal consortium. D. communis showed a great vitality in the wastewater effluents with a biomass productivity of 0.138–0.227 g L−1 d−1 in the primary effluent enriched with CO2, higher biomass productivity compared with the one achieved by the algal consortium (0.078 g L−1 d−1). D. communis cultures reached also a better nutrient removal efficiency compared with the algal consortium culture, with almost 100% for ammonia and phosphorous at any N/P ratio characterizing the wastewater nutrient composition. Biomass composition was richer in polysaccharides and total fatty acids as the ammonia concentration in the water decreased. In view of a future application of this algal biomass, due to the low total fatty acids content of 1.4–9.3 wt% and the high C/N ratio of 7.6–39.3, anaerobic digestion appeared to be the most appropriate biofuel conversion process.