Calcium alginate is also used for entrapment of enzymes and forming artificial seeds in plant tissue culture.

[2] To extract the alginate, the seaweed is broken into pieces and stirred with a hot solution of an alkali, usually sodium carbonate.

The diluted extract is left standing for several hours while the air rises to the top, taking the residue particles with it.

This frothy mix of air and residue is removed from the top and the solution is withdrawn from the bottom and pumped to the filter.

[3] Because of their technological importance, the structure of calcium alginate hydrogels has long been a subject of scientific investigation.