Valorisation of microalga Tetradesmus obliquus grown in brewery wastewater using subcritical water extraction towards zero waste

In this study, green technology was applied for extraction of compounds from wastewater-grown microalga biomass with the final goal obtaining microbiologically safe products within a sustainable biorefinery process zero waste. Tetradesmus obliquus resulting brewery wastewater treatment, (To-CO2) and without CO2 supplementation (To), submitted to subcritical water (SWE) at temperatures 120–220 °C 10 min. The impact different SWE conditions in obtained liquid extracts solid residues were investigated metal content chemical microbiological profiles. Gas chromatography–mass spectrometry analysis indicated that T. are valuable sources aliphatic saturated, unsaturated, alkylated (mostly methylated) hydrocarbons, phenols, esters, ketones. Polyphenolic antioxidant activity enhanced approximately 4 times by increasing temperature 120 220 °C. Also, polyphenols doubled when supplemented all tested (To: 0.249–1.016 mg GAE mL?1; To-CO2: 0.437 – 1.767 mL?1). determined represent bioactive components can be used industries. addition, lower heavy metals suggests possibility using waste as animal feed or soil conditioner agricultural applications.