Liu Tingting, Shu Hong, Li Qian, Cui Zhao, Li Guangyue, Li Ting, Wang Yongdong, Sun Jing
Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang 421001, Hunan, China.
School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, Hunan, China.
Sheng Wu Gong Cheng Xue Bao. 2025 Aug 25;41(8):3081-3097. doi: 10.13345/j.cjb.250173.
MR-1, a Gram-negative bacterium with a significant role in the adsorption and reduction of uranium in wastewater and a quorum-sensing effect, can be used to remove uranium from wastewater. Exogenous signaling molecules (acyl-homoserine lactones, AHLs) can be added to induce the quorum sensing behavior for rapid biofilm formation, thereby improving the removal efficiency of this bacterium for uranium. Extracellular polymeric substances (EPS), as the significant components of biofilm, play a key role in biofilm formation. To investigate the quorum sensing behavior induced by AHLs, we systematically investigated the effects of AHLs on the EPS secretion and biofilm properties of . MR-1 by regulating parameters such as AHL species, concentration, addition time point, and contact time. The results showed that the addition of 10 μmol/L N-butyryl-l-homoserine lactone (C4-HSL) after 6 h of culture and continued incubation to reach the time point of 72 h significantly promoted the secretion of EPSs, in which the content of extracellular proteins and extracellular polysaccharides was increased by 15.2% and 28.2%, respectively, compared with that of the control group. The biofilm electrodes induced by signaling molecules showed superior properties, which were evidenced by an increase of exceeding 20 μm in biofilm thickness, an increase of 33.9% in the proportion of living cells, enhanced electroactivity, and an increase of 10.7% in the uranium removal rate. The biofilm electrode was confirmed to immobilize uranium in wastewater mainly by electrosorption, physicochemical adsorption, and electro-reduction through characterization means such as X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). This study provides a new technical idea for the efficient recovery of uranium in wastewater and enriches the theoretical system of quorum sensing regulation of electroactive biofilms.
MR-1是一种革兰氏阴性菌，在废水中铀的吸附和还原以及群体感应效应方面具有重要作用，可用于从废水中去除铀。添加外源信号分子（酰基高丝氨酸内酯，AHLs）可诱导群体感应行为以快速形成生物膜，从而提高该细菌对铀的去除效率。胞外聚合物（EPS）作为生物膜的重要组成部分，在生物膜形成中起关键作用。为了研究AHLs诱导的群体感应行为，我们通过调节AHL种类、浓度、添加时间点和接触时间等参数，系统地研究了AHLs对MR-1的EPS分泌和生物膜特性的影响。结果表明，培养6 h后添加10 μmol/L N-丁酰基-L-高丝氨酸内酯（C4-HSL）并继续孵育至72 h时间点，显著促进了EPS的分泌，其中胞外蛋白和胞外多糖的含量分别比对照组增加了15.2%和28.2%。信号分子诱导的生物膜电极表现出优异的性能，生物膜厚度增加超过20 μm、活细胞比例增加33.9%、电活性增强以及铀去除率提高10.7%证明了这一点。通过X射线光电子能谱（XPS）和傅里叶变换红外光谱（FTIR）等表征手段证实，生物膜电极主要通过电吸附、物理化学吸附和电还原将废水中的铀固定。本研究为废水中铀的高效回收提供了一种新的技术思路，丰富了电活性生物膜群体感应调控的理论体系。
