Abstract Sinai's important geographical and strategic position is attracting researchers to explore opportunities to maximize exploitation of its treasures, especially in the area of sustainable development. One of the fields of exploitation is extracting valuable metals from low-grade ores using green technologies. In this study, we examined the possibility of microbial leaching of uranium (U) from a rock sample collected from Wadi Naseib, Sinai, Egypt. Twenty previously isolated and tentatively identified native microorganisms, 10 Streptomyces and 10 Aspergillus , were used to make U-bioleaching using cells (direct) and cell metabolites (indirect). The tested isolates showed variable U-bioleaching efficiencies and the highest results was attained via the indirect method (57.2 ± 9.2% and 83.6 ± 2.3%) using two isolates that were identified genotypically as Streptomyces sp. EGY1 and Aspergillus niveus EGY2 respectively. TEM images showed that cells of A. niveus EGY2 made biomineralization, biosorption and bioaccumulation of U. The present study revealed that neither high acid production nor high phosphatase activities guarantees a high U-bioleaching efficiency. Many factors affecting the process were also studied using A. niveus EGY2. The highest U-bioleaching efficiency (87.8 ± 8.7%) was attained using pH 9, 160 rpm of both culturing and bioleaching steps, rock particle size of above 700 µm and 1% pulp density. U was recovered from leach liquor after optimization experiments using NaOH and its concentration was 64.35%. Our study revealed that Aspergillus niveus EGY2 could be promising in future scaling-up studies and pilot trials using the tested rock sample. Graphic Abstract

中文翻译：

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使用一些天然链霉菌和曲霉物种对西奈半岛岩石样品中的铀进行生物浸出研究

摘要 西奈半岛的重要地理位置和战略地位吸引着研究人员探索机会以最大限度地开发其宝藏，尤其是在可持续发展领域。开采领域之一是使用绿色技术从低品位矿石中提取有价值的金属。在这项研究中，我们研究了从埃及西奈半岛 Wadi Naseib 收集的岩石样本中微生物浸出铀 (U) 的可能性。20 种先前分离和初步鉴定的天然微生物，10 种链霉菌属和 10 种曲霉属，用于使用细胞（直接）和细胞代谢物（间接）进行 U 生物浸出。测试的分离株显示出不同的 U 生物浸出效率，通过间接方法获得最高结果（57.2 ± 9.2% 和 83.6 ± 2。3%) 使用两种在基因上被鉴定为链霉菌属的分离株。分别是EGY1和黑曲霉EGY2。TEM 图像显示 A. niveus EGY2 细胞对 U 进行了生物矿化、生物吸附和生物积累。本研究表明，高产酸和高磷酸酶活性均不能保证高 U 生物浸出效率。还使用 A. niveus EGY2 研究了影响该过程的许多因素。使用 pH 值 9、160 rpm 的培养和生物浸出步骤、700 µm 以上的岩石粒径和 1% 的纸浆密度获得最高的 U 生物浸出效率 (87.8 ± 8.7%)。用NaOH优化实验后从浸出液中回收U，其浓度为64.35%。我们的研究表明，Aspergillus niveus EGY2 可能在未来使用测试岩石样品的放大研究和试点试验中大有希望。图形摘要