Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aquaculture Spirulina sp. LEB 18 cultivation in outdoor pilot scale using aquaculture wastewater: High biomass, carotenoid, lipid and carbohydrate production Lucas Guimarães Cardoso a, ⁎ , Jessica Hartwig Duarte b , Bianca Bomfm Andrade a , Paulo Vitor França Lemos a , Jorge Alberto Vieira Costa b , Janice Izabel Druzian c , Fabio Alexandre Chinalia a a Institute of Health Sciences, Department of Biotechnology, Federal University of Bahia, Salvador, Brazil b Laboratory of Biochemical Engineering, College of Chemistry and Food Engineering, Federal University of Rio Grande, Rio Grande, Brazil c Graduate Program in Food Science, Faculty of Pharmacy, Federal University of Bahia, Salvador, Bahia, Brazil ARTICLEINFO Keywords: Aquaculture wastewater Spirulina Carbohydrate Bioremediation ABSTRACT The objective of this study was to integrate the treatment of aquaculture efuent with the biomass and mac- ronutrients production by Spirulina sp.LEB18.Thefrstexperimentwascarriedoutinaphotobioreactor(1L) andthebestbiomassproductionconditionwasreproducedonapilotscaleinaracewaytypebioreactor(5L). The best treatment was T25 (100% of wastewater supplemented with 25% of Zarrouk nutrients). The biomass production in the raceway system (T25) was higher (3.33 g L −1 ) than the control (2.32 g L −1 ) and the car- bohydrate (69.77%) and lipid (12.77%) were also higher. The content of carotenoids in T25 was signifcant (9.68 μg mL −1 ). Spirulina sp. LEB 18 removed phosphate (99.97%); COD (89.34%) and nitrate (81.10%) from aquacultureefuent.TheefuentshowedabsenceofheavymetalsandconcentrationofAl;Fe;CaandMghigher than the control culture with Zarrouk nutrients. The Spirulina sp. LEB 18 can be applied as a bioremediation agent of aquaculture wastewater with high production of biomass, carbohydrate, lipid and carotenoid. 1. Introduction Data from FAO (2018) show that the aquaculture industry is the fastest-growing food production sector in the world, responsible for 47% of the world's fsh production. The estimate is that by 2030 aquaculture contributes with 60% of fsh production for human con- sumption. However, all this production has the environmental cost of usinglargequantitiesofwaterandthelaunchingofhighnutrientrates in the environment. This discharge contains high concentrations of ammonia (3–7 mg L −1 ), nitrates (2–110 mg L −1 ) and phosphate (2–50 mg L −1 ) and COD (100–150 mg L −1 ) favorable to microalgae growth (Zhang et al., 2019). Microalgae such as Spirulina platensis have chemical characteristics such as high protein content (~ 70%), lipids (3–9%), carbohydrates (15–30%),β-carotene(superiortocarrots)andvitamins(includingB1, B2 and B12). This excellent Spirulina biomass composition allows a wide application, including human and animal feeding, moving ap- proximately30to60billiondollarsannually(PokhrelandSoni,2017). The study by Wuang et al. (2016) have pointed out the possibility of applying Spirulina cultivation in biological treatment of wastewater, achieving more than 90% of nutrients removal. Nur et al. (2019) ob- tainedC-phycocyanin(C-PC)productivity(4.08 ± 1.3mgL −1 day −1 ) in Arthrospira platensis cultivatedinasemi-continuoussystemwith50% Palm oil mill efuent (POME) at the frst stage and 100% POME. Thesestudiesusedmicroalgaeduetoadvantagessuchasreduction in sludge formation, biomass production, carbon dioxide fxation, gas emissionsreductionandlowenergyconsumption.Theseadvantagesled to extensive studies on the removal of diferent pollutants by these microorganisms (Kumaretal.,2017).However,fewstudieshavebeen done evaluating wastewater from aquaculture on the synthesis of spe- cifc biomolecules by microalgae. Mohammadi et al. (2019) evaluated the efect ofarawefuent mixture with diferent slurry ratios in the Desmodesmus spp. and Scenedesmus obliquus biomass production, showing high content of lipids (20%) and carbohydrates (41%) in the biomass. Facedwiththis,thepresentstudyaimedtointegratethetreatment of aquaculture efuent with the production of Spirulina sp. LEB 18 biomass, promoting as well the increase of specifc macronutrients production. For the frst time, treatment of aquaculture wastewater through microalgae is used to accumulate specifc biomolecules. https://doi.org/10.1016/j.aquaculture.2020.735272 Received 23 January 2020; Received in revised form 19 March 2020; Accepted 20 March 2020 ⁎ Corresponding author at: Institute of Health Sciences, Department of Biotechnology, Federal University of Bahia (UFBA), Salvador, Bahia, Brazil. E-mail address: lucaseng.pesca@yahoo.com.br (L.G. Cardoso). Aquaculture 525 (2020) 735272 Available online 26 March 2020 0044-8486/ © 2020 Elsevier B.V. All rights reserved. T