Single-step extraction of carotenoids from brown macroalgae using non-ionic surfactants

Abstract

While there is an accrued interest in the production and application of bioactive compounds from macroalgae, several of these compounds with high industrial and commercial interest remain underexplored. Carotenoids (and specifically fucoxanthin) normally found in brown macroalgae are examples of these compounds. One of the major issues associated with the poor commercial exploitation of these biomolecules is the need for a highly performant and low cost extraction process to extract them selectively from the algal biomass. In this work, aqueous solutions of various non-ionic surfactants were screened for the carotenoids extraction. Moreover, and after the selection of the most performant surfactants, several processing conditions, namely the solid-liquid ratio, concentration of surfactant and time of extraction were evaluated. The optimal conditions were applied to the extraction of carotenoids for both Portuguese and Brazilian algae species. With the process of extraction developed in this work, that was optimized for the dry seaweed biomass but it is also applicable to the fresh one, extraction results of 5.28 ± 2.01 mgcarotenoids/gbiomass for Tomadol 25-7 and 1.86 ± 0.06 mgcarotenoids/gbiomass for Pluronic P-123 were obtained. Despite the higher extraction efficiency of the conventional (ethanol-based) method (6.48 ± 0.01 mgcarotenoids/gbiomass), the methodology proposed in this work allows a much higher selectivity of the carotenoids extraction since, unlike with ethanol, less contaminants (in particular chlorophylls) are extracted along with the carotenoids. This work proposes a simpler (with less extraction steps), more selective and organic solvent-free extractive process to recover carotenoids from brown macroalgae, directly applicable to fresh biomass.