Abstract Nowadays, microbial exopolysaccharide (EPS) have been extensively researched due to their multifunctional characteristics, especially the EPS from the lactic acid bacteria (LAB). However, the EPS from the Oenococcus oeni (O. oeni, a lactic acid bacteria commonly used in winemaking) have rarely been experimented. In this study, the EPS produced by O. oeni 28A-1 was obtained and characterized. The EPS had an average molecular weight of 7.73×104 Da and were composed of mannose, rhamnose, glucose, galactose, arabinose and galacturonic acid in a molar ratio of 13.6:1.3:8.8:5.6:1:1.4. The SEM images showed EPS appeared as irregular lamellar structure and coarse surface. The AFM image of the EPS showed that the irregular particle structure was dispersed in the solution, and some aggregation occurred in some areas. FT-IR analysis of the EPS revealed the characteristics of polysaccharide with the presence of specific functional groups. The EPS also exhibited higher thermal stability with a degradation temperature of 259.47°C in DSC analysis. In addition, the EPS from O. oeni exhibited great lyoprotective ability during its freeze-drying process, which indicated its great potential to be developed as natural lyoprotectant for O. oeni.

中文翻译：

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oenococcus oeni 28A-1胞外多糖的部分表征和冻干保护活性

摘要 目前，微生物胞外多糖（EPS）因其多功能特性而得到广泛研究，尤其是来自乳酸菌（LAB）的EPS。然而，来自 Oenococcus oeni（O. oeni，一种常用于酿酒的乳酸菌）的 EPS 很少进行实验。在本研究中，获得并表征了 O. oeni 28A-1 产生的 EPS。EPS的平均分子量为7.73×104 Da，由甘露糖、鼠李糖、葡萄糖、半乳糖、阿拉伯糖和半乳糖醛酸以13.6:1.3:8.8:5.6:1:1.4的摩尔比组成。SEM图像显示EPS表现为不规则的层状结构和粗糙的表面。EPS 的 AFM 图像显示不规则颗粒结构分散在溶液中，并且在某些区域发生了一些聚集。EPS的FT-IR分析揭示了具有特定官能团的多糖的特征。EPS 还表现出更高的热稳定性，DSC 分析中的降解温度为 259.47°C。此外，O. oeni 的 EPS 在其冷冻干燥过程中表现出很强的冻干保护能力，这表明其作为 O. oeni 的天然冻干保护剂具有巨大的潜力。