Optimization of the rope seeding method and biochemical characterization of the brown seaweed Asperococcus ensiformis

Abstract

The consumption of seaweed has grown notably due to its use in the food, cosmetic and pharmaceutical industries, as well as organic fertilizers and biofuel, among others. Species of Asperococcus have antioxidant and antitumor properties and synthesize abundant amounts of fucoidans with important anticoagulant properties. In this study, the biochemical characterization of the A. ensiformis sporophytes was performed: organic matter, alginates, fucoidans, total carbohydrates and proteins content, pigments, polyphenols and antioxidant activity. Also, its life cycle was described and the best culture conditions were identified to optimize the hatchery phase. Three incubation temperatures 8, 12 and 16 °C and six nutrient concentrations were evaluated: three with Provasoli culture medium (PES) and three with PES + Kelpak® (a commercial biostimulant based on algae). Asperococcus ensiformis presented a heteromorphic life cycle, alternating between microscopical branched filaments (gametophytic phase) and an erect macroscopic stage (sporophytic phase). The biochemical composition of the A. ensiformis sporophytes showed a relatively low carbohydrate and protein content, but a high yield of alginates and fucoidans, and high polyphenol content and antioxidant activity. In the culture assays, the highest survival and colonization on seed-rope of gametophytes were achieved at 12 °C and high PES concentrations. The colonization of sporophytes on the seed-ropes at the end of the experiment was similar at the different temperatures, but the highest survival and growth were at 8 °C and low PES and PES + Kelpak® concentrations. This study emphasizes the need to analyze the industrial potential of A. ensiformis, through its biochemical characterization and optimization of crops, using different temperatures and traditional nutrients, as well as biostimulants based on seaweeds.