Sargassum delignification: a first step to mitigate the socio-economic and environmental impacts in the Caribbean through its sustainable exploitation

Massive blooms of pelagic Sargassum in Caribbean shores cause several economic and environmental affectations. Their industrial exploitation could help to mitigate the negative impacts associate with their accumulation; however, their utilization had been limited due the presence of a recalcitrant polyphenolic net (lignin). So, this study was focused on the development of a treatment with mild operation conditions which reduce the lignin content facilitating the production of value-added compounds under a zero-waste scheme. The treatment was carried out with hydrogen peroxide (H 2 O 2 ) as oxidant reagent; it is cheaper than other reagents and during their reaction, the only products are oxygen and water; their concentration and retention time were evaluated achieving delignification yields from 30.72 to 75.43%. The best conditions for Sargassum delignification were 3 h and 10% (v/v) of H 2 O 2 . Infrared specters and thermogravimetrical analysis confirmed the remotion of the recalcitrant material. As well, micrographs obtained by the scanning electronic micrograph prove that the treatment removes the layer which covers the carbohydrates matrix. The industrial applications of the oxidative process could help to turn the Sargassum crisis into an opportunity, contributing to the mitigation of the environmental and socioeconomic impacts. Graphical Abstract