Alginic acid

Alginic acid, also called algin, is a naturally occurring, edible <a href="/facts/Polysaccharide/lqXq2cJU">polysaccharide</a> found in <a href="/facts/Brown_algae/u4PWxxkC">brown algae</a>. It is <a href="/facts/Hydrophilic/k8p95WYu">hydrophilic</a> and forms a viscous <a href="/facts/Natural_gum/nyNzLTuc">gum</a> when hydrated. When the alginic acid binds with sodium and calcium ions, the resulting salts are known as alginates. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular, or powdered forms. 
It is a significant component of the <a href="/facts/Biofilms/zg93x2w4">biofilms</a> produced by the bacterium <a href="/facts/Pseudomonas_aeruginosa/HBhyIxAn">Pseudomonas aeruginosa</a>, a major pathogen found in the lungs of some people who have <a href="/facts/Cystic_fibrosis/tlNK5BAH">cystic fibrosis</a>. The biofilm and P. aeruginosa have a high resistance to <a href="/facts/Antibiotics/sF1kIfxg">antibiotics</a>, but are susceptible to inhibition by <a href="/facts/Macrophages/z7hkQu3o">macrophages</a>.
Alginate was discovered by British chemical scientist E. C. C. Stanford in 1881, and he patented an extraction process for it in the same year. The alginate was extracted, in the original patent, by first soaking the algae in water or diluted acid, then extracting the alginate by soaking it in <a href="/facts/Sodium_carbonate/P6RHvIoK">sodium carbonate</a>, and finally precipitating the alginate from solution.[better source needed]

Alginic acid open-in-new

Alginic acid