Reducing the consumption of fresh water in the process of alginate extraction using Macrocystis pyrifera (Phaeophyta, Laminariales), by recirculating the residual liquids from the pre-extraction and precipitation

The recirculation of the residual liquid from the pre-extraction stage and precipitation using samples of Macrocystis pyrifera was studied to reduce the consumption of fresh water in the process of alginate extraction in the laboratory. An average yield of 28.44% was obtained with three recirculations in the pre-extraction stage, with a saving of 25% in the consumption of fresh water and of 56.25% in the consumption of concentrated hydrochloric acid. The consumption of fresh water was reduced by 50% with three recirculations of the residual liquid from the precipitation in the alkaline extraction stage, with an average yield of sodium alginate of 33.45%. The sodium alginates obtained had high viscosity and pH values within the maximum stability range (pH 5-9).