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−1 of 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.

Spirulina as Animal Feed: Opportunities and Challenges

“…Nonetheless, improvements are needed to make production more sustainable. To this end, research continues to improve sustainability by including biogas effluent [ 34 ] or wastewater [ 35 ] as nutrient sources. As spirulina requires warm temperature (35–37 °C) for cultivation [ 36 ], integrating waste heat sources, such as is produced during biogas production, also has the potential to optimize cultivation facilities within Europe [ 37 ].…”

Utilização do resíduo de malte da indústria cervejeira como meio alternativo para o cultivo da Spirulina platensis e Spirulina máxima

“…O teor de PUFA foi maior para as duas espécies de Spirulina cultivadas no meio RM variando de 57 a 59%. Hultberg et al (2017), obtiveram concentrações maiores de ácidos graxos insaturados na biomassa produzida com o meio à base de efluentes para Spirulina sp. Matos (2017); Paliwal et al (2017), afirmam que a quantidade dos PUFAs varia com a espécie e condições de cultivo e ainda que está intimamente relacionada à composição química do meio de cultivo.…”

Effects of Liquid Digestate Treatment on Sustainable Microalgae Biomass Production

“…[50] obtained 2.05 g/L biomass yield using the same genus of algae and digestate. In turn, the maximum final biomass production of A. platensis grew 10 days on anaerobic digestate from a commercial biogas plant based on plant residues obtained from local agriculture was as low as 1.5 g TS/L [51]. Nonetheless, the comparison of the biomass yields achieved is not straightforward, due to the different growth conditions applied (e.g., light intensity, the experimental time, digestate characteristic) significantly affecting the microalgae growth.…”