Abstract Molybdenum, a precious metal with important roles in industries, is projected to experience future shortage. Despite this, there is still no practical recycling process of this metal and around 25 thousand tons of molybdenum are discharged into wastewater annually. Biorecovery is a promising approach to resolve the above problem because of its high selectivity, high sensitivity, low running cost and low environmental burden. A bacterial molybdenum binding protein ModE has been constructed into yeast cells and named as ScBp5. In this study, the potential of genetic engineered yeast for recovering molybdenum from wastewater was further investigated. In order to stabilize the expression of ModE, strain ScBp5 was further modified by replacing promoter upstream of modE to generate ScBp6. The improvement of molybdenum adsorption efficiency by ScBp6 was confirmed especially in low concentration. The molybdenum isotherms parameters of ScBp6 was analyzed. To enable the usage as biorecovery agent in industrial settings, ScBp6 cells were immobilized using calcium alginate matrix, and the optimum immobilization conditions for ScBp6 were determined as 2% matrix density, 4 h of immobilization time, and 10 mg/ml cell density. The investigation of molybdenum adsorption kinetics by immobilized ScBp6 cells showed this adsorption was an efficient chemisorption. Overall, this research demonstrate the efficiency of immobilized yeast cell in molybdenum recovery.

中文翻译：

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使用固定化生物工程酿酒酵母回收钼酸盐

摘要 钼是一种在工业中具有重要作用的贵金属，预计未来会出现短缺。尽管如此，这种金属仍然没有实用的回收工艺，每年约有 2.5 万吨钼被排放到废水中。生物回收具有高选择性、高灵敏度、低运行成本和低环境负担等优点，是解决上述问题的一种有前景的方法。一种细菌钼结合蛋白 ModE 已被构建到酵母细胞中并命名为 ScBp5。在这项研究中，进一步研究了基因工程酵母从废水中回收钼的潜力。为了稳定ModE的表达，通过替换modE上游的启动子来进一步修饰菌株ScBp5以产生ScBp6。ScBp6 对钼吸附效率的提高尤其在低浓度下得到证实。分析了 ScBp6 的钼等温线参数。为了能够在工业环境中用作生物回收剂，使用海藻酸钙基质固定 ScBp6 细胞，并将 ScBp6 的最佳固定条件确定为 2% 基质密度、4 小时固定时间和 10 mg/ml 细胞密度。固定化 ScBp6 细胞对钼吸附动力学的研究表明，这种吸附是一种有效的化学吸附。总的来说，这项研究证明了固定化酵母细胞在钼回收方面的效率。ScBp6 细胞使用海藻酸钙基质固定，ScBp6 的最佳固定条件确定为 2% 基质密度、4 小时固定时间和 10 mg/ml 细胞密度。固定化 ScBp6 细胞对钼吸附动力学的研究表明，这种吸附是一种有效的化学吸附。总的来说，这项研究证明了固定化酵母细胞在钼回收方面的效率。ScBp6 细胞使用海藻酸钙基质固定，ScBp6 的最佳固定条件确定为 2% 基质密度、4 小时固定时间和 10 mg/ml 细胞密度。固定化 ScBp6 细胞对钼吸附动力学的研究表明，这种吸附是一种有效的化学吸附。总的来说，这项研究证明了固定化酵母细胞在钼回收方面的效率。