Welan gum is a microbial product that occupies an important position among extracellular polysaccharides due to its novel properties and potential applications. The biopolymer Welan gum is synthesised by a fermentation process mainly by alkali producing bacteria of the genus Alcaligenes sp. It consists of a tetrasaccharide backbone chain polymer containing L-mannose, L-rhamnose, D-glucose and D-glucuronic acid. It is an anionic polysaccharide and therefore has polyelectrolyte properties due to the presence of d-glucuronic acid in its chemical structure[1].
Welan gum has commercial applications in the field of cement systems. It acts as a thickener, suspending agent, binder and emulsifier, stabiliser and viscosity builder. It also has potential applications in oil well drilling as it maintains its stability and viscosity at high temperatures[1].
[1] VARINDER KAUR . Welan gum: Microbial production, characterization, and applications[J]. International Journal of Biological Macromolecules, 2014, 65: Pages 454-461. DOI:10.1016/j.ijbiomac.2014.01.061.
