title: Use of the effluent from biogas production for cultivation of Spirulina.
abstract: The effluent from the biogas process was tested as a nutrient source during cultivation of the protein-rich and edible microalgae Spirulina (Arthrospira platensis) and compared with conventional Spirulina medium. Equal biomass production was observed until late exponential phase and no significant differences could be observed between the treatments in protein amount, amino acid composition, and total lipid concentration. The concentration of the pigment phycocyanin differed significantly between Spirulina medium and the effluent-based medium (63.3 ± 11.7 and 86.2 ± 1.9 mg g-1, respectively). Slightly higher concentrations of saturated fatty acids, mainly palmitic acid, were observed in the biomass produced in Spirulina medium than in that produced in the effluent-based medium. In the biomass produced in the effluent-based medium, the cadmium concentration was 0.07 ± 0.05 mg kg-1of dry weight, whereas it was below the detection limit in the biomass produced in Spirulina medium. There is a need to identify new food and feed resources and a possible future scenario is to integrate Spirulina production into the biogas plant for protein production as it contains more than 60% of protein on dry weight basis. In that scenario, it is important to control heavy metal concentrations in the biogas slurry fed to Spirulina.
authors.affiliation: Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P.O. Box 103, 230 53, Alnarp, Sweden. Malin.Hultberg@slu.se.
authors.forename: Malin
authors.identifier: http://orcid.org/0000-0001-7634-6102
authors.initials: M
authors.lastname: Hultberg
authors.affiliation: Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P.O. Box 103, 230 53, Alnarp, Sweden.
authors.forename: Olle
authors.initials: O
authors.lastname: Lind
authors.affiliation: Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Birgersson
authors.affiliation: Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P.O. Box 103, 230 53, Alnarp, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Asp
mesh_terms: D056804:Biofuels; D003470:Culture Media / Q000737:chemistry*; D058086:Microalgae / Q000254:growth & development*; D053545:Spirulina / Q000254:growth & development*
chemical_list: D056804:Biofuels; D003470:Culture Media
keywords: Anaerobic digestate effluent; Arthrospira platensis; Biofertiliser; Microalgae; Nutrient recycling