Microwave hydrothermal processing of the invasive macroalgae Sargassum muticum within a green biorefinery scheme

Abstract

This study deals with the multiproduct valorization of the invasive macroalgae Sargassum muticum within a green biorefinery concept using microwave hydrothermal treatment. Temperatures of 160 and 180 ◦C for 0–60 min (severities 1.62–3.54) were evaluated, allowing a recovery of a liquid phase rich in fucoidan-derived compounds (up to 4.81 g/L), oligomers and phenolics with antioxidant capacity (up to 2.85 g TE/L by ABTS assay), and a high-enzymatically susceptible solid (glucan to glucose conversion 76–100% in 9 h) suitable for bioethanol production (20.5 g/L in 18 h, corresponding to 96% ethanol yield). Moreover, energy consumption of the pre-treatments’ temperature–time binomial was evaluated showing significant differences, demonstrating the ad-vantages of microwave as alternative heating pretreatment