Spirulina sp. as a Bioremediation Agent for Aquaculture Wastewater: Production of High Added Value Compounds and Estimation of Theoretical Biodiesel Lucas Guimarães Cardoso 1 & Jessica Hartwig Duarte 2 & Jorge Alberto Vieira Costa 2 & Denilson de Jesus Assis 3 & Paulo Vitor França Lemos 1 & Janice Izabel Druzian 4 & Carolina Oliveira de Souza 4 & Itaciara Larroza Nunes 5 & Fabio Alexandre Chinalia 1 Received: 20 March 2020 /Accepted: 9 June 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract The rapid development of large-scale aquaculture leads to wastewater accumulation, increasing environmental problems. Microalga cultivation is a potential biotechnological alternative to treat aquaculture wastewater. While this microorganism consumes the wastewater nutrients, high added value biomass is produced. The role of Spirulina in aquaculture wastewater treatment is not fully elucidated in the literature. Thus, this study aimed to reuse and treat aquaculture wastewater by Spirulina sp. LEB 18 cultures. The microalga growth parameters, the biochemical composition of the biomass produced, and the Spirulina efficiency to nutrient removal from the aquaculture wastewater were evaluated. The assays were performed in closed photobioreactors (1 L) using 100% aquaculture wastewater (T-0) supplemented with 25 (T-25), 50 (T-50), and 75% (T-75) of the Zarrouk synthetic culture medium. The maximum biomass concentrations showed no statistical difference between the assays T-50 (1.02 g L -1 ), T-25 (1.10 g L -1 ), and control (1.05 g L -1 ). The biomass from the T-25 assay showed the highest concentrations of protein (65.73%), phycocyanin (16.60 mg/mL), polyunsaturated fatty acid (38.20%), and γ-linolênico (23.29%). Besides that, the Spirulina sp. LEB 18 highest removal rate of sulfate (94.01%), phosphate (93.84%), bromine (96.77%), and COD (90.00%) was obtained from the T- 25 assay. The biomass from T-25 and T-50 assays showed ideal properties for biodiesel application. The Spirulina sp. LEB 18 cultures using 100% aquaculture wastewater supplemented with 25% of Zarrouk culture medium was the best option for the aquaculture wastewater treatment, producing added value biomass and reducing production cost. Keywords Biofuel . Biomass composition . Microalgae . Nutrient removal . Wastewater treatment Highlights • Spirulina sp. LEB 18 showed maximum biomass concentration in 100% wastewater aquaculture with 25% of Zarrouk (1.10 g L -1 ); • Biomass production with higher values of protein (65.73%) and phycocyanin (16.60 mg/mL); • High levels of polyunsaturated fatty acids (38.20%) and C18:3n6 (38.20%); • High removal rates 94.01% (sulfate s); 93.84% (Phosphate); 96.77% (Bromine) and 90.00% (COD); • T-25 treatment with quality biodiesel properties. * Lucas Guimarães Cardoso cardoso.lucas@ufba.br 1 Department of Biotechnology, Institute of Health Sciences, Federal University of Bahia, Salvador, Bahia, Brazil 2 Laboratory of Biochemical Engineering, College of Chemistry and Food Engineering, Federal University of Rio Grande, Rio Grande, Brazil 3 School of Architecture, Engineering and Information Technology, Salvador University, Salvador, Bahia, Brazil 4 Graduate Program in Food Science, Faculty of Pharmacy, Federal University of Bahia, Salvador, Bahia, Brazil 5 Graduate Program in Food Science, Department of Food Science and Technology, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil BioEnergy Research https://doi.org/10.1007/s12155-020-10153-4