A marine yeast, Yarrowia lipolytica isolated from an oil polluted sea water and shown earlier to sequester dissolved uranium (U) at pH 7.5, was utilized in the present study for developing an immobilized-cell process for U removal from aqueous solutions under batch and continuous flow through systems. In batch system, optimum biosorption conditions for U removal were assessed by investigating the effects of biomass dose, initial U concentration, contact time and pH of solution using Y. lipolytica cells immobilized in calcium alginate beads. Appreciable uranium-binding capabilities over a wide pH range (3-9) were observed with the alginate beads bearing yeast cells. Out of Langmuir and Freundlich models employed for describing the sorption equilibrium data under batch mode, uranyl adsorption followed Langmuir approach with satisfactory correlation coefficient higher than 0.9. Uranyl adsorption kinetics by Y. lipolytica entrapped in alginate beads was best described by the pseudo-second-order model. While the environmental scanning electron microscopy established the immobilization and the uniform distribution of Y. lipolytica cells in the alginate beads, the Energy Dispersive X-ray spectroscopy analysis confirmed the deposition of U in the beads following their exposure to uranyl solution. Fixed bed flow-through column comprising of Y. lipolytica biomass immobilized in polyacrylamide matrix displayed high efficacy for continuous removal of uranium at pH 7.5 up to five adsorption-desorption cycles. Adsorbed U by immobilized cells could be significantly desorbed using 0.1 N HCl. Overall, our results present the superior efficiency of immobilized Y. lipolytica biomass for U removal using batch and regenerative approaches.

中文翻译：

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通过固定化的热带海洋酵母解脂耶氏酵母（Yarrowia lipolytica）生物量去除铀。

从本研究中利用海洋酵母，从油污染的海水中分离出来的解脂耶氏酵母，并在更早的时间显示其螯合了pH 7.5的溶解铀（U），用于开发固定化细胞工艺，用于分批连续地从水溶液中去除U流经系统。在分批系统中，使用固定在藻酸钙珠粒中的解脂耶氏酵母细胞，通过研究生物量剂量，初始U浓度，接触时间和溶液的pH值，评估了去除U的最佳生物吸附条件。用带有酵母细胞的藻酸盐珠观察到在宽的pH范围（3-9）内具有明显的铀结合能力。在用于描述批处理模式下吸附平衡数据的Langmuir和Freundlich模型中，尿烷基吸附遵循Langmuir方法，相关系数高于0.9。拟二级模型最好地描述了藻酸盐微珠中截留的解脂耶氏酵母对铀酰的吸附动力学。尽管环境扫描电子显微镜确定了藻酸盐微珠中解脂耶氏酵母细胞的固定和均匀分布，但能量分散X射线光谱分析证实了U暴露于铀酰溶液后微珠中的U沉积。由固定在聚丙烯酰胺基质中的解脂耶氏酵母生物质组成的固定床流通柱显示了在连续五个吸附-解吸循环下，在pH 7.5下连续去除铀的高效性。固定细胞吸附的U可以使用0.1 N HCl显着解吸。总体，