Production of selenium-enriched microalgae as potential feed supplement in high-rate algae ponds treating domestic wastewater

Jun Li; Lila Otero-Gonzalez; Joris Michiels; Piet N L Lens; Gijs Du Laing; Ivet Ferrer

doi:10.1016/j.biortech.2021.125239

Production of selenium-enriched microalgae as potential feed supplement in high-rate algae ponds treating domestic wastewater

Bioresour Technol. 2021 Aug:333:125239. doi: 10.1016/j.biortech.2021.125239. Epub 2021 Apr 28.

Authors

Jun Li¹, Lila Otero-Gonzalez², Joris Michiels³, Piet N L Lens⁴, Gijs Du Laing², Ivet Ferrer⁵

Affiliations

¹ Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium; GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya·BarcelonaTech, Jordi Girona 1-3, Building D1, 08034 Barcelona, Spain. Electronic address: Jun.Li@UGent.be.
² Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
³ Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium.
⁴ UNESCO-IHE Institute for Water Education, 2601 DA Delft, the Netherlands.
⁵ GEMMA-Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya·BarcelonaTech, Jordi Girona 1-3, Building D1, 08034 Barcelona, Spain.

PMID: 33940503
DOI: 10.1016/j.biortech.2021.125239

Abstract

This study assessed the selenium (Se) removal efficiency of two pilot-scale high-rate algae ponds (HRAPs) treating domestic wastewater and investigated the production of Se-enriched microalgae as potential feed supplement. The HRAP-Se had an average Se, NH₄⁺-N, total phosphorus and COD removal efficiency of, respectively, 43%, 93%, 77%, and 70%. Inorganic Se taken up by the microalgae was mainly (91%) transformed to selenoamino acids, and 49-63% of Se in the Se-enriched microalgae was bioaccessible for animals. The crude protein content (48%) of the microalgae was higher than that of soybeans, whereas the essential amino acid content was comparable. Selenium may induce the production of the polyunsaturated fatty acids omega-3 and omega-6 in microalgae. Overall, the production of Se-enriched microalgae in HRAPs may offer a promising alternative for upgrading low-value resources into high-value feed supplements, supporting the drive to a circular economy.

Keywords: Algae; HRAPs; Photobioreactor; Resource recovery; Selenium; Wastewater treatment.

MeSH terms

Biomass
Microalgae*
Ponds
Selenium*
Wastewater

Substances

Waste Water
Selenium