Does the subject want to ask "Alginate contains carboxyl groups"? Containing carboxyl groups. Alginate, also known as alginic acid, alginic acid and alginic acid, is a natural polysaccharide existing in the cell wall of brown algae. Alginate is a kind of polymer with carboxyl and hydroxyl groups at the same time. Common brown algae such as kelp, Sargassum, Bulbophyllum and macroalgae are the main sources of alginic acid.