The salt content is not a limitation for ensiling sargassum collected in the mexican caribbean

Abstract

Since 2011, sargassum has been infesting the coasts of the Mexican Caribbean, affecting the environment, human health, and economic activities. However, sargassum can be used via different processes to obtain alginates, fucoidans, biofuels, agricultural fertilizers, and livestock feed. Nevertheless, the quantity and composition of the sargassum that reaches the coasts of the Mexican Caribbean present a high seasonal variation, which hinders its industrial exploitation. Therefore, to ensure a supply of sargassum susceptible to industrial processing, the pretreatment conditions for its conservation through ensiling were determined. Among them, inoculum addition, sargassum desalination, and the incorporation of additives were evaluated. In sargassum without pretreatment, inoculum addition cannot effectively lower the pH in the silo. In contrast, glucose addition (~261 mg/gdm) in washed sargassum enriched with nutrient solution allows a pH decrease up to ~4.8, reaching an average glucose bioconversion to lactic acid above 68 %. Similar results were obtained when ensiling sargassum without washing, reaching the maximum decrease in pH after 10 d. In addition, low contents of acetic acid (< 20 mg/gdm) and ethanol (< 8 mg/gdm) were registered in these silos, indicating a low activity of other microorganisms. Therefore, adequate sargassum silage requires the addition of inoculant, glucose, and nutrient.