6. Conclusions

During this collaboration between two public research laboratories (LEMIRE, CERMAV) and a private company (ARD), a bacterial strain and the polysaccharide it produces were identified and studied in detail in order to define and develop a range of applications. The polysaccharide is branched and carries carboxyl groups which make it a polyelectrolyte sensitive to salt effects. In addition, its chemical regularity, based on a repeating unit of seven sugars, two of which are in the side chain, leads to a locally rigid chain that exhibits a helical conformation at room temperature.

In acid form, the polysaccharide behaves viscoelastically in solution, with a thermoreversible helix structure; in fully deacetylated form, the conformation is disordered into a ball and viscosities remain low in solution. In sodium salt form, the heat-treated native polymer evolves and heat...