Application of Green Technology to Extract Clean and Safe Bioactive Compounds from Tetradesmus obliquus Biomass Grown in Poultry Wastewater

Jelena Vladić; Jelena Molnar Jazić; Alice Ferreira; Snežana Maletić; Dragoljub Cvetković; Jasmina Agbaba; Senka Vidović; Luisa Gouveia

doi:10.3390/molecules28052397

Application of Green Technology to Extract Clean and Safe Bioactive Compounds from Tetradesmus obliquus Biomass Grown in Poultry Wastewater

Molecules. 2023 Mar 6;28(5):2397. doi: 10.3390/molecules28052397.

Authors

Jelena Vladić¹, Jelena Molnar Jazić², Alice Ferreira³, Snežana Maletić², Dragoljub Cvetković¹, Jasmina Agbaba², Senka Vidović¹, Luisa Gouveia^{3

4}

Affiliations

¹ Department of Biotechnology and Pharmaceutical Engineering, Faculty of Technology, University of Novi Sad, 21000 Novi Sad, Serbia.
² Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia.
³ Laboratório Nacional de Energia e Geologia IP, UBB-Bioenergy and Biorefineries Unit, Estrada Paço Lumiar, Edificio G, 1649-038 Lisbon, Portugal.
⁴ GreenCoLab-Green Ocean Technologies and Products Collaborative Laboratory, Centro de Ciências do Mar do Algarve, Universidade do Algarve Campus Gambelas, 8005-139 Faro, Portugal.

Abstract

Microalgae are capable of assimilating nutrients from wastewater (WW), producing clean water and biomass rich in bioactive compounds that need to be recovered from inside the microalgal cell. This work investigated subcritical water (SW) extraction to collect high-value compounds from the microalga Tetradesmus obliquus after treating poultry WW. The treatment efficiency was evaluated in terms of total Kjeldahl nitrogen (TKN), phosphate, chemical oxygen demand (COD) and metals. T. obliquus was able to remove 77% TKN, 50% phosphate, 84% COD, and metals (48-89%) within legislation values. SW extraction was performed at 170 °C and 30 bar for 10 min. SW allowed the extraction of total phenols (1.073 mg GAE/mL extract) and total flavonoids (0.111 mg CAT/mL extract) with high antioxidant activity (IC₅₀ value, 7.18 µg/mL). The microalga was shown to be a source of organic compounds of commercial value (e.g., squalene). Finally, the SW conditions allowed the removal of pathogens and metals in the extracts and residues to values in accordance with legislation, assuring their safety for feed or agriculture applications.

Keywords: antioxidants; metal removal; microalgae; nutrient recycling; organic profile; subcritical water extraction.

MeSH terms

Animals
Biomass
Chlorophyceae*
Metals
Microalgae*
Nitrogen
Phosphates
Poultry
Technology
Wastewater
Water

Substances

Wastewater
Water
Metals
Phosphates
Nitrogen

Grants and funding

This research was supported by the project funded by the Provincial Secretariat for Science and Technological Development, Autonomous Province of Vojvodina, Serbia 142-451-2576/2019-02; Bilateral project Portugal-Serbia 5554/2020 (FCT) and 337-00-00227/2019-09/72 (Serbia); the project ALGAVALOR—Lisboa-01-0247-FEDER-035234, supported by Operational Programme for Competitiveness and Internationalization, by Lisbon Portugal Regional Operational Programme and by Algarve Regional Operational Programme under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund; Biomass and Bioenergy Research Infrastructure—LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness and Internationalization, by Lisbon Portugal Regional Operational Programme (Lisboa 2020) and by North Portugal Regional Operational Programme under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund; Red CYTED P319RT0025—RENUWAL—Red Iberoamericana para el Tratamiento de Efluentes con Microalgas and Bilateral Portugal-India—WCalgae⁺KIT—DRI/India/0609/2020—Combination of Vertical Wetlands, Microalgae Photobioreactor and Microbial Fuel Cell (KIT) for wastewater treatment in small pig production farms Alice Ferreira is pleased to acknowledge her PhD grant no. SFRH/BD/144122/2019 awarded by Fundação para a Ciência e Tecnologia.