FAQs

Detail the production process of gellan gum and explain the critical importance of the deacylation step.

The commercial manufacture of gellan gum is a sophisticated biotechnology process. The bacterium Pseudomonas elodeais cultivated under sterile, aerobic conditions in a fermenter containing a defined medium with a carbon source (like glucose), a nitrogen source, and mineral salts. Parameters such as aeration, agitation, pH, and temperature are precisely controlled to optimize polysaccharide synthesis. Following fermentation, the broth is heat-treated to inactivate the culture. The recovery and purification process dictates the final product's properties. A pivotal step is controlled deacylation, typically achieved through mild alkaline treatment. This process removes the O-acyl groups (acetate and glycerate) from the polymer backbone. The resulting low-acyl gellan gum yields firm, brittle, and highly thermostable gels, which are the basis for its major commercial applications in food and microbiology. In contrast, the native, high-acyl form produces soft, elastic, and thermoreversible gels. This controlled modification allows producers to engineer the fundamental gelling character, providing two distinct texture platforms from a single fermentation source.