State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Department of Chemical and Biomolecular Engineering, Ohio University, Athens, OH, USA.
Extremophiles. 2022 Jun 29;26(2):22. doi: 10.1007/s00792-022-01270-3.
High metal ion concentrations and low pH cause severely inhibit the activity of an acidophilic microbial consortium (AMC) in bioleaching. This work investigated the effects of exogenous spermine on biofilm formation and the bioleaching efficiency of LiCoO by AMC in 9K medium. After the addition of 1 mM spermine, the activities of glutathione peroxidase and catalase increased, while the amount of HO, intracellular reactive oxygen species (ROS) and malondialdehyde in AMC decreased. These results indicated that the ability of AMC biofilm to resist oxidative stress introduced by 3.5 g/L Li and 30.1 g/L Co was improved by spermine. The activity of glutamate decarboxylase was promoted to restore the intracellular pH buffering ability of AMC. Electrochemical measurements showed that the oxidation rate of pyrite was increased by exogenous spermine. As a result, high bioleaching efficiencies of 97.1% for Li and 96.1% for Co from a 5.0% (w v) lithium cobalt oxide powder slurry were achieved. This work demonstrated that Tafel polarization can be used to monitor the AMC biofilm's ability of uptaking electrons from pyrite during bioleaching. The corrosion current density increased with 1 mM spermine, indicating enhanced electron uptake by the biofilm from pyrite.
高金属离子浓度和低 pH 值会严重抑制嗜酸微生物联合体（AMC）在生物浸出中的活性。本研究考察了外源精胺对 AMC 在 9K 培养基中生物膜形成和 LiCoO 生物浸出效率的影响。添加 1mM 精胺后，谷胱甘肽过氧化物酶和过氧化氢酶的活性增加，而 AMC 中 HO、细胞内活性氧（ROS）和丙二醛的含量减少。这些结果表明，精胺提高了 AMC 生物膜抵抗 3.5g/L Li 和 30.1g/L Co 引起的氧化应激的能力。谷氨酸脱羧酶的活性得到促进，以恢复 AMC 的细胞内 pH 缓冲能力。电化学测量表明，外源精胺能提高黄铁矿的氧化速率。因此，从 5.0%（w/v）的氧化锂钴粉末浆液中获得了 97.1%的 Li 和 96.1%的 Co 的高生物浸出效率。本研究表明，塔菲尔极化可用于监测生物浸出过程中 AMC 生物膜从黄铁矿中摄取电子的能力。随着 1mM 精胺的加入，腐蚀电流密度增加，表明生物膜从黄铁矿中摄取的电子增加。
