The influences of extracellular polymeric substances (EPS) on heavy metal ions biosorption by acidophilic microorganisms have not been systematically reported previously. In this study, three acidophilic strains were chosen as model microbes to evaluate the effect of EPS on the adsorption of heavy metal ions (Cu²⁺, Ni²⁺, Cd²⁺, Zn²⁺) from aqueous solutions. The results indicated that buffering capacities and protonation/deprotonation abilities of these acidophiles were enhanced in the presence of EPS. Acid–base titration and FTIR analysis revealed the carboxyl, phosphoryl, amino and hydroxyl groups have provided EPS binding sites for heavy metal ions via deprotonation. The extreme thermophilic archaea had the highest total site concentration of 7.93 ± 0.52 × 10⁻⁴ mol/g on the cell surface. Meanwhile, cells with EPS had better performance in adsorption when compared with cells without EPS. The biosorption abilities of the extreme thermophilic archaea with EPS toward Cu²⁺, Ni²⁺, Cd²⁺ and Zn²⁺ were 48 μmol/g, 37.5 μmol/g, 32.5 μmol/g and 28 μmol/g, respectively. This study could provide theoretical support for the treatment of heavy metal ions in acid mine drainage by acidophiles.

以前尚未系统地报道过细胞外聚合物（EPS）对嗜酸性微生物生物吸附重金属离子的影响。在本研究中，选择了三个嗜酸菌株作为模型微生物，以评估EPS对重金属离子（Cu 2 ⁺，Ni 2 ⁺，Cd 2 ⁺，Zn ²⁺）。结果表明，在EPS存在下，这些嗜酸菌的缓冲能力和质子化/去质子化能力得到增强。酸碱滴定法和FTIR分析表明，羧基，磷酰基，氨基和羟基基团通过去质子化作用为重金属离子提供了EPS结合位点。极端嗜热古细菌 在细胞表面的最高总位点浓度为7.93±0.52×10 ^-4 mol / g。同时，与没有EPS的细胞相比，具有EPS的细胞具有更好的吸附性能。EPS极端嗜热古细菌对Cu 2 ⁺，Ni 2 ⁺，Cd ²⁺和Zn ²⁺的生物吸附能力分别为48μmol/ g，37.5μmol/ g，32.5μmol/ g和28μmol/ g。该研究可为嗜酸菌处理酸性矿山排水中的重金属离子提供理论支持。