Paramylon

Paramylon] is a glucose polymer similar to cellulose, but they differ in how the glucose (or glucan) units are linked. Cellulose contains β-1→4 glucan linkages, whereas in paramylon, the glucan linkages are in the β-1→3 configuration.

Paramylon is found in microalgae of the genus Euglena, single-cell flagellate eukaryotes that grow in salt- and freshwater. Botanist Bastiaan J. D. Meeuse at Delft University of Technology (the Netherlands) did early work on the characterization of paramylon. As reported in a 1965 article, Meeuse and co-workers isolated the molecule from E. spirogyra by comminuting it in a blender, suspending the particles in water, shaking the suspension in butyl alcohol, and isolating pure paramylon granules from the aqueous layer.

The 1→3 bonding in paramylon allows the polymer to self-organize into a triple helix, as illustrated in the image at the right. Paramylon molecules extracted from Euglena spp. tend to have very uniform chain lengths.

Materials chemist Motonari Shibakami at the National Institute of Advanced Industrial Science and Technology (AIST, Tsukuba, Japan) is developing paramylon-based materials for potential commercialization. The materials include nanofibers, thermoplastic films, optical lenses, fibers, and adhesives. These applications have small carbon footprints compared with fossil feedstock sources and are cost-effective because of the ease of cultivating Euglena organisms and extracting paramylon from them.

For more information about paramylon processing see a review by Eric Leroy and coauthors at the University of Nantes (Carquefou, France) and the University of Reims Champagne–Ardenne (Reims, France).