黑曲霉浸铀过程中的形态特征及其对铀浸出的影响

Morphology Properties of Aspergillus niger During Bioleaching of Uranium and Its Effect on Uranium Extraction

黑曲霉(A.niger)在深层培养时具有复杂的生长形态,其直接影响黑曲霉的代谢产能。然而,黑曲霉浸矿过程中的形态特征及其对浸出效果的影响还未得到重视。通过黑曲霉浸铀的单因素实验,考察浸出时间、孢子接种量、碳源种类与用量、初始pH值、矿浆浓度对黑曲霉的形态特征与铀浸出的影响,分析两者之间关系。结果表明,在不同的浸出条件下,黑曲霉呈现出3种不同形态:紧实的生物矿石颗粒、松软的生物矿石颗粒和散状菌丝,当铀矿粉被黑曲霉完全包裹形成紧实的生物矿石颗粒时,铀的浸出率最高。在浸出时间4 d、孢子接种量1×108 spores·L^-1、蔗糖浓度25 g·L^-1、初始pH 6、矿浆浓度2%的条件下,可形成紧实的生物矿石颗粒,铀的浸出率达76.26%。

Aspergillus niger(A. niger) exhibits a complex morphology in suspended culture, which directly influences its metabolic productivity. However, no attention has been paid to the morphological properties of A. niger during the leaching process and its effect on leaching efficiencies of uranium so far. Bioleaching of uranium from its ore using A. niger was carried out through single-factor experiments. The effects of leaching time, spore inoculum, type and concentration of carbon source, initial pH and pulp density on uranium extraction and the morphological characteristics of A. niger were investigated, and their relationship was also examined. The results showed that A. niger had three morphologies under different leaching conditions, including compact bio-ore pellets, loose bio-ore pellets and dispersed mycelia. The compact bio-ore pellets exhibited the highest uranium extraction as the ore was completely coated with the hypha of A. niger. Under the conditions of 4 days leaching time, spore inoculum of 1×108 spores·L^-1, sucrose concentration of 25 g·L^-1, initial pH 6 and pulp density of 2%, the compact bio-ore pellets were formed and uranium recovery was up to 76.26%.