Effect of carbon source on production, characterization and bioactivity of exopolysaccharide produced by Phellinus vaninii Ljup

ABSTRACT The effect on different three carbon source (i.e. glucose, fructose and sucrose) on production, chemical characterization and antioxidant activity of exopolysaccharide (EPS) produced by Phellinus vaninii Ljup was investigated in this study. Amongst carbon sources examined, glucose and sucrose were favorable for the mycelia growth, while the maximum EPS yield was achieved when sucrose was employed. The predominant carbohydrate compositions in EPSs identified were gluconic acid, glucose, mannose and galactose acid. Then, FT-IR spectral analysis revealed prominent characteristic groups in EPSs. EPSs molecule exist as nearly globular shape form in aqueous solution. The variation also affects antioxidant activities by investigated by using hydroxyl and DPPH radical scavenging assay. Sucrose was best carbon source from the viewpoint of antioxidant activity due to the relatively high contents of galactose in the EPS with moderate molecular weight and polydispersity.

摘要 本研究探讨了三种不同碳源（即葡萄糖、果糖和蔗糖）对斑褐孔菌（Phellinus vaninii Ljup）所产胞外多糖（exopolysaccharide, EPS）的产量、化学特性及抗氧化活性的影响。在所测试的碳源中，葡萄糖与蔗糖均利于菌丝生长，而以蔗糖为碳源时可获得最高的EPS产量。已鉴定的EPS样品中主要碳水化合物成分为葡萄糖酸、葡萄糖、甘露糖与半乳糖酸。傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy, FT-IR）分析结果显示，EPS具有显著的特征官能团。EPS分子在水溶液中近似呈球形结构。本研究通过羟基自由基与DPPH自由基清除试验，考察了碳源差异对EPS抗氧化活性的影响。从抗氧化活性角度来看，蔗糖为最优碳源，这是因为其所产EPS的半乳糖含量相对较高，且分子量适中、多分散性良好。