Synthesis of the Microbial Polysaccharide Gellan from Dairy and Plant-Based Processing Coproducts

Author(s)/Creator(s)

Thomas P. West

Publication Title

Polysaccharides

Document Type

Article

Abstract/Description

The purpose of this review is to provide both background about the microbial polysaccharide gellan and, more specifically, to examine bacterial gellan synthesis on dairy and plant-based processing coproducts. The anionic heteropolysaccharide gellan is known to be synthesized by Sphingomonas elodea strain ATCC 31461 [1,2]. Although originally classified as Pseudomonas elodea, this strain was reclassified as a species of Sphingomonas [3,4]. Structurally, the water-soluble gum gellan exists as a tetrasaccharide composed of 20% glucuronic acid, 60% glucose and 20% rhamnose [5–7]. The native form of gellan has been shown to contain acetyl and L-glyceryl groups. These substituents need to be removed by an alkaline heat treatment to produce a gel. The degree of deacetylation of gellan can be directly correlated to its gel-forming ability [8]. The alkaline treatment of the native biopolymer results in a tetrasaccharide sequence that is anionic (Figure 1). As the deacylated biopolymer cools, a double helix forms from the disordered coils which results in gelation. Gelation of the polysaccharide is enhanced when the pH of the polysaccharide becomes more acidic. An acidic pH diminishes the negative charge of the polysaccharide molecule that results in greater repulsion within the helix. The addition of monovalent cations to a gellan solution increases its rate of gelation [9–14].

Department

Chemistry

First Page

234

Last Page

244

DOI

10.3390/polysaccharides2020016

Volume

2

Issue

2

ISSN

2673-4176

Date

4-6-2021

Citation Information

West, Thomas P., "Synthesis of the Microbial Polysaccharide Gellan from Dairy and Plant-Based Processing Coproducts" (2021). Faculty Publications. 192.
https://digitalcommons.tamuc.edu/cose-faculty-publications/192