The aim of this study was to characterize the exopolysaccharide (EPS) produced by Bacillus velezensis SN-1 (B. velezensis SN-1) (EPS-SN-1), which was isolated from the fermented Da jiang. The microbe made crude exopolysaccharides EPS-SN-1 was produced throughout the bacterial growth period, and the highest yield (2.7 g/L) was obtained with sucrose as the carbon source. As per high performance liquid chromatography (HPLC), EPS-SN-1 is a heteropolysaccharide consisting of glucose, mannose and fructose, with a high molecular weight of 2.21 × 10⁵ Da. FTIR spectra further indicated the presence of hydroxyl and carbonyl groups, and NMR analysis confirmed both α- and β-glycosidic bonds. Furthermore, differential scanning calorimetry (DSC) showed that EPS-SN-1 has high thermal stability with fusion point of 270.7 °C. Finally, EPS-SN-1 demonstrated strong antioxidant capacity via its ability to scavenge hydroxyl radical (^•OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) radical, ABTS radical (ABTS^•+) and oxygen radical (O₂^−•). Taken together, EPS-SN-1 is a promising natural antioxidant and probiotic with potential applications in the food industry.

中文翻译：

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velezensis SN-1芽孢杆菌SN-1自发发酵大江产的新型胞外多糖的结构表征和抗氧化能力。

这项研究的目的是表征由发酵大江分离得到的Velacensis Bacillus velezensis SN-1（B. velezensis SN-1）（EPS-SN-1）产生的胞外多糖（EPS）。在整个细菌生长期，都生产出微生物制得的粗制胞外多糖EPS-SN-1，以蔗糖为碳源可获得最高产量（2.7 g / L）。根据高效液相色谱（HPLC），EPS-SN-1是由葡萄糖，甘露糖和果糖组成的杂多糖，具有2.21×10 ^5的高分子量 大。FTIR光谱进一步表明存在羟基和羰基，并且NMR分析证实了α-和β-糖苷键。此外，差示扫描量热法（DSC）显示EPS-SN-1具有高的热稳定性，其熔点为270.7℃。最后，EPS-SN-1通过清除羟自由基（^• OH），1,1-二苯基-2-吡啶并肼基（DPPH ^•），ABTS自由基（ABTS ^•+）和氧自由基（O _2- ^•）。两者合计，EPS-SN-1是一种有前途的天然抗氧化剂和益生菌，在食品工业中具有潜在的应用。