DEVELOPMENT OF THE APPROACHES FOR COMPLEX UTILIZATION OF BROWN ALGAE (FUCUS VESICULOSUS) BIOMASS FOR THE OBTAINING OF VALUE-ADDED PRODUCTS

Abstract

The seaweed collected after stranding on beaches of Latvia is underexploited natural resource, which has a potential as raw material for biologically active compound extraction for cosmetic and pharmacy and fertilizer in sustainable agriculture. The aim of the present study was development of the approach for the processing of brown alga Fucus vesiculosus biomass, collected from the Gulf of Riga. The thorough characterization of the chemical composition of Fucus vesiculosus has shown that it is a potential source for obtaining of nitrogen-containing fertilizers, and biologically active compounds. One of the proposed approaches for the processing of the Fucus vesiculosus biomass under study includes algae extraction with organic solvents and CaCl₂ solution and obtaining soil organic amendment on the basis of the extract-free residue. The ethyl acetate extract was rich in phenolic compounds (430 ± 30 GAE mg/g) with high antioxidant activity in DPPH^• and ABTS^•+ tests. The ethanol extract contained significant amounts of phlorotannins that was confirmed by the data of LC-MS/MS analysis. The CaCl₂ extract was used for the obtaining of sulphated polysaccharide fucoidane (yield ≈7% on the basis of oven dry matter, o.d.m.), which has numerous biological activities. The extract-free residue didn’t show phytotoxicity. The extract free algal biomass exhibited positive effect in root elongation tests with oat (Avena sativa). As alternative approach for processing of the algal biomass, the mechano-chemical treatment of algal biomass with lignin was proposed. EPR analyses confirmed interaction between algal biomass and lignin.

Keywords: Fucus vesiculosus, extracts, antioxidants, organic fertilizers, biorefinery

Article DOI: http://doi.org/10.15544/RD.2017.091