Screening of microalgae with potential for biodiesel production and nutrient removal from treated domestic sewage E.B. Sydney a,1 , T.E. da Silva a,1 , A. Tokarski a,1 , A.C. Novak a,1 , J.C. de Carvalho a,1 , A.L. Woiciecohwski a,1 , C. Larroche b , C.R. Soccol a,⇑ a Bioprocess Engineering and Biotechnology Department, Federal University of Paraná, Centro Politécnico, Usina Piloto B, CEP 81531-990 Curitiba, Paraná, Brazil b Biochemical Engineering Department, School of Engineering, Blaise Pascal University, Clermont-Ferrand, France article info Article history: Received 29 September 2010 Received in revised form 11 November 2010 Accepted 19 November 2010 Available online 18 December 2010 Keywords: Microalgae Screening Nitrogen Phosphorus Wastewater Lipid abstract This article reports the results of the screening of microalgae capable of removing nitrogen and phospho- rus while accumulating lipids in effluents from secondary domestic wastewater treatment. Twenty strains were tested for their growth capacity; the growth parameters of 13 strains were determined, and the following three strains were selected and cultivated in photobioreactors: the isolated and unknown LEM-IM 11, Botryococcus braunii and Chlorella vulgaris. The capacity of each strain to remove nitrogen and phosphorus as well its growth rate and biomass composition was determined. B. braunii LEM 14 showed the best combined results and is a good candidate for the development of a large-scale process. From the treated domestic wastewater, 79.63% of the nitrogen and phosphorus was removed after 14 days of culture at 25 °C. Biomass composition indicated an oil accumulation (36% dry weight) and high carbon uptake (144.91 mg CO 2 g 1 biomass L 1 day 1 ). Fatty acid methyl ester analysis showed a pre- dominance of palmitic (C16:0) and oleic (C18:1) acids, with considerable amounts of stearic (C18:0), lin- oleic (C18:2) and alpha-linolenic (C18:3) acids. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction In the last 70 years, microalgae have been widely studied because of their metabolic versatility and capacity for carbon diox- ide mitigation. The large scale depletion of fossil fuels has caused climate change. Recently, this has prompted interest in the development of new clean technologies allowing for the commer- cialization of carbon credits and the co-generation of commercial products from microalgae. Recent developments have shown the potential of microalgae for the production of a variety of active compounds, such as vita- mins, pigments, carotenoids, proteins, aminoacids, lipids, polysac- charides, biofuels and others. However, the industrial cultivation of microalgae faces an economic feasibility issue because of the high price of artificial medium and the low levels of biomass produc- tion. Thus, the utilization of natural complex media (those for which the composition is not determined) is an interesting alterna- tive that possesses the added benefit of associating microalgal pro- duction with wastewater treatment. In the Brazilian context, three residues produced in large quan- tities are of interest for alga fuel production. The first is vinasse, a liquid residue from the ethanol industry, which is generated after alcohol distillation at a scale of 12–15 L for each liter of ethanol produced. Vinasse is primarily composed of minerals such as potassium, sulfate, calcium, phosphorus, magnesium, iron and nitrogen, which are the same as those used in artificial media for algae production. In 2009/2010, Brazil produced 20.4 billion liters of ethanol, which corresponds to roughly 250 billion liters of vin- asse. This high level of production, which is expected to increase in the future, has been associated with many environmental issues due to its disposal requirements and the possibility for its use in microalgal cultures. Integrated processes that explore these as- pects for the production of oleaginous microalgae and CO 2 recy- cling (Patent PI0706144-7 [1] and Patent PI0804611-5A2 [2]) were recently developed in our laboratory. The second byproduct of interest is the liquid residue from the cassava processing industry. Studies have been carried out that demonstrate the possibility of the production of oil and protein- rich microalgae biomass (Patent PI0805091-0A2 [3]). Finally, domestic wastewater is a residue of interest for biofu- els production from microalgae. Microalgae ponds can be used in secondary or tertiary treatment. This would bring advantages such as cost effectiveness, low energy requirements, reduction in sludge formations, greenhouse gas mitigation and the produc- tion of useful microalgal biomass. Wastewater production by hu- man activity is ubiquitous, and the continuous increase in world 0306-2619/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.apenergy.2010.11.024 ⇑ Corresponding author. Tel.: +55 41 33613191. E-mail addresses: soccol@ufpr.br, arriba@globo.com (C.R. Soccol). 1 Tel.: +55 41 33613191. Applied Energy 88 (2011) 3291–3294 Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy