副球菌TH21-44胞外多糖的结构表征及其抗氧化活性探究

Structural characterization of exopolysaccharide from Paracoccus sp.TH21-44 and its antioxidant activity

针对副球菌(Paracoccus sp.)TH21-44所产胞外多糖(exopolysaccharide,EPS),通过离子交换层析分离纯化,结合全波段扫描、电子显微镜、高效液相色谱及凝胶渗透色谱等,解析其化学组分和结构,并探究TH21-44 EPS对DPPH、ABTS+以及羟自由基清除能力和还原能力,评估TH21-44 EPS的抗氧化活性。结果表明,副球菌TH21-44的EPS由两种多糖组分构成,其中EPS-1为主成分,其总糖占比92.63%,并含有少量蛋白和硫酸盐,表观结构呈现粗糙且致密多孔的片状或树杈状,单糖组成以葡萄糖、半乳糖和甘露糖为主;抗氧化结果表明,EPS-1在5 mg/mL浓度时,对DPPH和羟自由基的清除力分别为59.61%和78.55%,EPS-1为3 mg/mL浓度时对ABTS清除力达99.36%,与Vc持平。本研究结果可为微生物胞外多糖的菌种资源开发和应用提供参考。

The exopolysaccharides(EPS)produced by Paracoccus sp.TH21-44 were isolated and purified by ion�exchange chromatography,and their chemical components and structure were analyzed by full-wave scanning,electron microscopy,high-performance liquid chromatography and gel permeation chromatography.The antioxidant activities of TH21-44 EPS was also evaluated in terms of DPPH,ABTS+,hydroxyl radical scavenging,and reduction abilities to assess its antioxidant potential.The results showed that the EPS of Paracoccus sp.TH21-44 consisted of two polysaccharide fractions,of which EPS-1 was the main component with 92.63%of total sugars,along with small amounts of protein and sulfate.The rough and dense porous structure of EPS-1 appeared flaky or branched.The monosaccharide composition of EPS-1 was dominated by glucose,galactose and mannose.The antioxidant results showed that TH21-44 EPS removed 59.61%of DPPH and 78.55%of hydroxyl radicals at a concentration of 5 mg/mL,and EPS-1 showed ABTS scavenging ability of 99.36%at a concentration of 3 mg/mL,equivalent to that of Vc.These findings provides valuable insights for the utilization of microbial exopolysaccharides as bioresources.