Algin and Alginates

Abstract

Algin was first discovered by Stanford in the early 1880’s and there is little doubt that the event was the beginning of a new era in the use of seaweeds. Stanford, when he first prepared this substance, did not succeed in obtaining it in the pure state, and because of the impurities he described it as a nitrogen-containing compound. It was later properly prepared by Krefting (1896), who thought he had a new substance which he called ‘tangsaure’, or seaweed acid. In the seaweeds the algin is present as a mixed salt of sodium and/or potassium, calcium and magnesium. The exact composition varies with algal species. Since Stanford discovered algin, the name has been applied to a number of substances, e.g. alginic acid, all alginates, sodium alginate, etc., derived from alginic acid. It has been suggested (Tseng, 1945a) that it is desirable to reserve the name algin for the soluble sodium salt of alginic acid, and it will be so used here. In recent years the amount of information has been accumulating at a very high rate. It now appears that algin production may not be restricted to marine algae as Larsen and Howe (1972) have found it in Azotobacter vinelandii.