Development of Nanocellulose Hydrogels from Sargassum Seaweed as Controlled Nutrient Release Systems and their Application in Germination.

Sargassum algae, being able to proliferate without the need to be attached to a substrate, travel through the ocean generating massive stagnations on the Caribbean coasts of the continent, becoming an environmental problem. Because its composition mainly includes polysaccharides, such as cellulose and hemicellulose, these algae were used to produce nanocellulose and create hydrogels to apply to germination. This article aims to develop of nanocellulose hydrogels from Sargassum and study the effect of it adding nanocellulose hydrogels from Sargassum algae loaded with Ca-PO₄- and NO₃ as nutrients in the germination process. The Sargassum algae used underwent two hydrolysis processes, one basic and one acid, with which it was possible to increase the cellulose content from 25.7 ± 0.42% to 34.05 ± 0.39 after the first hydrolysis and after 90.15 ± 0.44% after the second. Size reduction to nanocellulose was performed employing an ultrasonic homogenizer sonicator. The obtained nanocellulose was characterized using infrared spectroscopy, X-ray diffraction, and transmission electron microscopy, showing that by the alkaline method, the sizes were between 135-190 nm while by the acid method, the fiber sizes were between 108-163 nm with a difference of 1.04 in the crystallinity index between the two hydrolyses. With the nanocellulose, hydrogels were formed using 5%, 10%, and 15% borax as crosslinking agents. Drying curves and scanning electron microscopy were performed on the hydrogels. Nutrients Ca-PO₄-NO₃ were added to the hydrogel and their release in water was studied through Ultraviolet-Visible spectrophotometry, with which it was decided to use the hydrogel containing 10% borax in the germination study. The effect of the hydrogel loaded with nutrients on the germination of bean and linseed seeds employing a complete factorial design 23. Obtaining results that the nutrient with the greatest influence on germination was nitrogen while the nutrient with the least favorable results was the match. [ABSTRACT FROM AUTHOR]