Elleuch Jihen, Drira Marwa, Ghribi Imtinen, Hadjkacem Farah, Pierre Guillaume, Causserand Christel, Khemakhem Hamadi, Michaud Philippe, Fendri Imen, Abdelkafi Slim
Laboratoire de Génie Enzymatique et Microbiologie, Equipe Biotechnologie des Algues, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, Sfax, Tunisia.
Laboratoire de Protection et Amélioration des Plantes, Centre de Biotechnologie de Sfax, Université de Sfax, B.P. 1177, 3018, Sfax, Tunisia.
Antonie Van Leeuwenhoek. 2025 Feb 3;118(3):51. doi: 10.1007/s10482-024-02057-6.
Microorganisms producing extracellular polymeric substances (EPS) are of great potential in numerous environmental applications. The present study explores the production and properties of extracellular polymeric substances (EPS) from Amphora coffeiformis diatom strain and their potential applications in environmental remediation. EPS were composed of a complex mixture of polysaccharides, proteins, humic substances and nucleic acids, with polyanionic characteristics as revealed by FTIR, Raman and zeta potential analyses. EPS showed high flocculation efficiency against kaolin clay at low dosages (5 mg/L) through a charge neutralization mechanism involving both polysaccharides and proteins. EPS also exhibited strong emulsification activity for various nonpolar substrates, mainly olive oil, corn oil, soybean oil, essence and diesel, with emulsification indexes above 80%. The emulsions were stable for 72 h under different NaCl concentrations (1-10% w/v). Moreover, EPS demonstrated remarkable adsorption capacity for lead, reaching a maximum of 1699.33 ± 89.61 mg/g under optimized conditions using Box-Behnken design. The adsorption mechanism involved multiple functional groups such as hydroxyl, carbonyl, carboxyl, phosphoric and sulfhydryl. Therefore, EPS from A. coffeiformis are a promising candidate for restoring environments contaminated by heavy metals.
产生胞外聚合物（EPS）的微生物在众多环境应用中具有巨大潜力。本研究探讨了咖啡形双眉藻硅藻菌株胞外聚合物（EPS）的产生、性质及其在环境修复中的潜在应用。EPS由多糖、蛋白质、腐殖质和核酸的复杂混合物组成，傅里叶变换红外光谱（FTIR）、拉曼光谱和zeta电位分析表明其具有聚阴离子特性。EPS通过涉及多糖和蛋白质的电荷中和机制，在低剂量（5mg/L）下对高岭土表现出高絮凝效率。EPS对各种非极性底物，主要是橄榄油、玉米油、大豆油、香精和柴油，也表现出很强的乳化活性，乳化指数高于80%。在不同NaCl浓度（1-10%w/v）下，乳液在72小时内保持稳定。此外，EPS对铅表现出显著的吸附能力，在使用Box-Behnken设计的优化条件下，最大吸附量达到1699.33±89.61mg/g。吸附机制涉及羟基、羰基、羧基、磷酸基和巯基等多个官能团。因此，咖啡形双眉藻的EPS是修复重金属污染环境的有前途的候选物。
