Characterization of Sargassum spp. from the Mexican Caribbean and Its Valorization through Fermentation Process

Sargassum is a brown macroalga that has become a general environmental problem in the Mexican Caribbean. Despite the negative effects on the beaches, the algae contain compounds of biotechnological and agronomic interest. The possibility of using sargassum as a substrate under liquid media fermentation (LMF) processes will allow the obtention of bioactive compounds. In this research, five species of Sargassum from the Puerto Morelos region were collected from the beach. The samples were divided into natural Sargassum and washed Sargassum, and the total phenolic compounds (TPC), flavonoids (F), and antioxidant capacity (AOxC) were determined. Once the material was characterized, it was fermented in the LMF process using the Aspergillus niger strain, where the obtained extracts were analyzed. Three holopelagic and one benthic species were identified. The proximal analysis of the seaweed in natural and washed conditions shows adequate carbon–nitrogen ratio values for use as a substrate for microbial degradation. Comparing the fermented extracts with fresh Sargassum, the analyses showed a TPC increase for washed Sargassum fermentation and a TPC decrease for natural Sargassum fermentation; the flavonoid content reached 8-fold higher in the washed Sargassum fermentation. An average AOxC of 57% was achieved during the washed Sargassum LMF process, with a maximum of 69% of ABTS inhibition. Considering these results, Sargassum can be used as a substrate in LMF processes to obtain bioactive compounds.