Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry 605014, India.
Bioresour Technol. 2011 Apr;102(7):4827-33. doi: 10.1016/j.biortech.2010.12.118. Epub 2011 Jan 14.
Optimum culture conditions which ease the synthesis of a novel exopolysaccharide (EPS) from a potent marine strain Streptococcus phocae was proposed in this study. The strain grows well at 35 °C, pH 7.0 and NaCl (2%) with lactose and yeast extract as best carbon and nitrogen sources. The maximum yield of EPS (11.75 and 12.14 g/L) was obtained in the presence of lactose and yeast extract at a concentration of 20 g/L respectively. EPS was refined by gel filtration chromatography using phenyl Sepharose column which revealed the presence of arabinose, fructose and galactose sugar units with molecular mass about 2.8 × 10(5) Da. Emulsifying and flocculating stability of EPS compared with three commercial hydrocolloids. EPS exhibited better activities which are similar to that of commercial hydrocolloids. Both crude and purified EPS exhibited strong antioxidant potential by quenching hydroxyl and superoxide anion radicals. Antibiofilm activity by inhibition of Gram positive and Gram negative biofilm forming bacteria was evident in our studies. Potential antioxidant activity and biofilm inhibiting property of EPS may lead to the development of novel food grade adjuncts.
本研究提出了一种优化的培养条件，以促进一种新型海洋链球菌（Streptococcus phocae）胞外多糖（EPS）的合成。该菌株在 35°C、pH7.0 和 2%NaCl 条件下生长良好，以乳糖和酵母提取物为最佳碳源和氮源。当乳糖和酵母提取物的浓度分别为 20 g/L 时，EPS 的最大产量（11.75 和 12.14 g/L）。使用苯基 Sepharose 柱通过凝胶过滤色谱法对 EPS 进行精制，结果表明 EPS 中存在阿拉伯糖、果糖和半乳糖糖单元，分子量约为 2.8×10^5 Da。与三种商业水凝胶相比，EPS 的乳化和絮凝稳定性。EPS 表现出较强的抗氧化活性，其活性与商业水凝胶相似。粗提和纯化的 EPS 通过淬灭羟自由基和超氧阴离子自由基表现出很强的抗氧化潜力。在我们的研究中，抑制革兰氏阳性和革兰氏阴性生物膜形成细菌的生物膜活性是明显的。EPS 的潜在抗氧化活性和生物膜抑制特性可能导致新型食品级添加剂的开发。
