Directed synthesis, characterization and rheological properties of an ultrahigh molecular weight acetylated-gellan
Yue Ming1, Zhuangzhuang Shi1, Weilong Wang1
1Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
Abstract:
Gellan gum (GG), a linear anionic heteropolysaccharide with gelling, stabilizing, and thickening properties, is widely used in food, pharmaceutical, and cosmetic industries. Development of its variants is of great interest due to the need for novel gellan gum for applications in some new scenarios. In this study, gellan gum variants containing only acetyl groups but no glyceryl groups were synthesized in a Sphingomonas sanxanigenens chassis NG via rational design. Additionally, the molecular weight (Mw) of gellan-NG was 1.49 ± 0.08 × 107 Da, far exceeding that of GG produced by the native strain Sphingomonas paucimobilis ATCC 31461 (~500 kDa). The characterization of texture and rheology showed that gellan-NG exhibited a stronger ability to maintain its own integrity and higher sol-gel transition temperature, indicating enhanced thermal stability and a more stable three-dimensional network structure. In conclusion, this study provides a reliable strategy for the directed synthesis of polysaccharides and clarifies the structure-property relationship of an ultrahigh molecular weight acetylated-gellan gum (named UMW-AG), laying a theoretical foundation for its practical application in high-performance polysaccharide-based materials.
