Abstract:

Surface-engineered yeast (Saccharomyces cerevisiae) cells were magnetically modified using water based magnetic nanoparticles to prepare a new type of magnetically responsive adsorbent. Infrared spectroscopy analysis revealed that magnetically modified cells remained the functional groups of engineered yeast and magnetic materials. The kinetic and adsorption isotherm law and factors influencing adsorption (such as time, temperature and pH) were analyzed. The results showed that adsorption equilibrium was achieved within 18 min. The optimal condition for the Ag⁺ adsorption was 20~30℃, pH 7.0. The pseudo-first-order kinetic model and Langmuir model fitted the adsorption data well. The results of multi-metal competitive adsorption indicated that magnetically modified cells still showed adsorption selectivity for Ag⁺ than other heavy metal ions. The adsorption amount of Ag⁺ was 10.6 times that of Ni²⁺, 9.0 times that of Zn²⁺, 7.5 times that of Co²⁺, 3.0 times that of Cu²⁺.

Key words: magnetic modification, surface-engineered yeast, silver, selective adsorption, magnetic separation

摘要：

采用水基磁性Fe₃O₄ 纳米颗粒修饰表面展示CueR蛋白的酿酒酵母(Saccharomyces cerevisiae), 获得磁响应性能良好的磁修饰工程酵母细胞。傅里叶变换红外光谱分析表明, 磁修饰细胞较好地保留了工程酵母细胞和磁性材料的官能团。研究吸附动力学、等温吸附模型以及不同因素(如时间、温度和pH值)对磁修饰细胞吸附Ag⁺的影响, 结果表明, 磁修饰酵母对Ag⁺的吸附速率很快, 18分钟基本上达到吸附平衡; 最适宜吸附温度为20~30℃; 最佳吸附pH值等于7。磁修饰酵母对Ag⁺的吸附符合准一级动力学模型和Langmuir等温吸附模型。多金属等摩尔浓度竞争条件下的吸附结果表明, 磁修饰后的工程酵母对Ag⁺仍具有选择吸附性, Ag⁺的吸附量为Ni²⁺的10.6 倍, Zn²⁺的9.0 倍, Co²⁺的7.5 倍, Cu²⁺的3.0 倍。

关键词: 磁修饰, 工程酵母, 银离子, 选择性吸附, 磁分离