Microalgae cultivation in thin stillage anaerobic digestate for nutrient recovery and bioproduct production

Anaerobically-digested thin-stillage, which is rich in nitrogen-ammonia (478 ± 11 mg L−1) and phosphorus (508 ± 5 mg L−1), offers great potential to be utilized as a source of nutrients for microalgae cultivation. However, the high concentration of ammonia is inhibitory to microalgal growth. In this...

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Bibliographic Details
Published in:Algal research (Amsterdam) 2020-05, Vol.47, p.101867, Article 101867
Main Authors: Sayedin, Farid, Kermanshahi-pour, Azadeh, He, Quan S., Tibbetts, Sean M., Lalonde, Crystal G.E., Brar, Satinder K.
Format: Article
Language:English
Subjects:
Bioproduct production
Microalgae cultivation
Nutrient recycling
Thin stillage digestate
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Summary:Anaerobically-digested thin-stillage, which is rich in nitrogen-ammonia (478 ± 11 mg L−1) and phosphorus (508 ± 5 mg L−1), offers great potential to be utilized as a source of nutrients for microalgae cultivation. However, the high concentration of ammonia is inhibitory to microalgal growth. In this study, ammonium present in the thin-stillage-digestate was partially recovered in the form of struvite to reduce the ammonia concentration to 267 ± 13 mg L−1 and to improve the nitrogen to phosphorus ratio from 2.1 to 14.4 for microalgae cultivation. Chlorella sorokiniana in two times dilution of struvite-removed-digestate achieved a biomass concentration of 1.62 ± 0.11 g L−1 and nutrient removal efficiencies of 95.3 ± 1% (nitrogen) and 78.3 ± 1.1% (phosphorous) at day 18. Protein, starch and lipid contents of C. sorokiniana biomass were 37.8 ± 3.4%, 17.8 ± 0.8% and 8.9 ± 0.3% of dry weight, respectively at day 18. Moreover, a dramatic increase in genera of Alcaligenes and Acinetobacter (known as nitrifying bacteria) was observed in bacterial populations during algal cultivation. •Chlorella sorokiniana was the most promising species to grow on thin stillage digestate.•Removal of struvite from digestate enhanced uptake of nutrients by microalgae.•Increase in nitrifying bacterial population was observed during algal cultivation.•Nitrogen and phosphorous removal efficiencies of 95.3 ± 1% and 78.3 ± 1.1% was achieved.•Protein, starch and lipid contents of biomass were 37.8 ± 3.4, 17.8 ± 0.8 and 8.9 ± 0.3%.
ISSN:2211-9264
2211-9264
DOI:10.1016/j.algal.2020.101867