Salt pan brine water sulphated polysaccharides retrieved at pilot scale: ability to stimulate in vitro human macrophages and salmon head kidney cells

Marine environments are the warehouse of a variety of novel bioactive compounds prone to be explored by food and feed industry. The growing interest in sulphated polysaccharides has led to the search for new sustainable sources, such as seawater. These compounds are naturally concentrated in salt pan brine water due to their evaporation by wind and sunlight. To take advantage of these sources, sulphated polysaccharides were concentrated from salt pan brine water using a scalable membrane ultrafiltration system with 30 and 100 kDa cut-off. This process allowed to concentrate ten times the polymeric material of brine water into 1.9 g/L, rendering a fluffy polysaccharide rich material after drying. It was mainly composed of 23 % (w/w) of uronic acids, 19 % of sulphate esters, and 34 % (w/w) of neutral sugars. This polymeric material has shown to stimulate in vitro both human macrophages and Atlantic salmon head kidney SHK-1 cells in a range of 6.25–50 μg/mL without toxicity, showing potential to be used in both human food and aquaculture feeding.