CEA, CNRS, Laboratory for Microbial Ecology (LEMiRE), Aix Marseille University, UMR7265 BIAM, F-13108 Saint-Paul-lez-Durance, France.
Research Unit Analytical BioGeoChemistry (BGC), Helmholtz Munich, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany.
Molecules. 2022 Oct 24;27(21):7172. doi: 10.3390/molecules27217172.
The current study examines the desiccation-resistant TTB310 as a model organism for the production of novel exopolysaccharides and their structural features. This bacterium is able to produce dividing forms of cysts which synthesize cell-bound exopolysaccharide. Initial experiments were conducted on the enrichment of cyst biomass for exopolysaccharide production under batch-fed conditions in a pilot-scale bioreactor, with lactate as the source of carbon and energy. The optimized medium produced significant quantities of exopolysaccharide in a single growth phase, since the production of exopolysaccharide took place during the division of the cysts. The exopolysaccharide layer was extracted from the cysts using a modified trichloroacetic acid method. The biochemical characterization of purified exopolysaccharide was performed by gas chromatography, ultrahigh-resolution mass spectrometry, nuclear magnetic resonance, and Fourier-transform infrared spectrometry. The repeating unit of exopolysaccharide was a decasaccharide consisting of ribose, glucose, rhamnose, galactose, mannose, and glucuronic acid with the ratio 3:2:2:1:1:1, and additional substituents such as acetyl, succinyl, and methyl moieties were also observed as a part of the exopolysaccharide structure. This study contributes to a fundamental understanding of the novel structural features of exopolysaccharide from a dividing form of cysts, and, further, results can be used to study its rheological properties for various industrial applications.
本研究以具有抗干燥能力的 TTB310 为模型生物，用于生产新型胞外多糖及其结构特征。该细菌能够产生分裂形式的芽孢，这些芽孢合成细胞结合的胞外多糖。最初的实验是在中试规模的生物反应器中，在分批进料条件下，以乳酸为碳源和能源，对芽孢生物量进行胞外多糖生产的富集。优化的培养基在单一生长阶段产生了大量的胞外多糖，因为胞外多糖的产生发生在芽孢的分裂过程中。使用改良的三氯乙酸法从芽孢中提取胞外多糖层。通过气相色谱、超高分辨率质谱、核磁共振和傅里叶变换红外光谱对纯化的胞外多糖进行生化特性分析。胞外多糖的重复单元是一种由核糖、葡萄糖、鼠李糖、半乳糖、甘露糖和葡萄糖醛酸组成的十糖，比例为 3:2:2:1:1:1，还观察到乙酰基、琥珀酰基和甲基等额外取代基作为胞外多糖结构的一部分。本研究有助于深入了解来自分裂形式的芽孢的新型胞外多糖的结构特征，并且可以进一步用于研究其流变性质，以应用于各种工业领域。
