Lei Wenliang, Liu Juan, Liu Yiwei, Xu Jing, Wang Wei
Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China.
School of Life Science, Shanxi University, Taiyuan 030006, China.
Int J Mol Sci. 2025 Apr 13;26(8):3685. doi: 10.3390/ijms26083685.
Heavy metal cadmium causes significant contamination in aquatic ecosystems. The biomineralization of cadmium represents a vital biological mechanism for handling cadmium stress in diverse microorganisms. To improve the biomineralization capacity of cadmium by microorganisms in aquatic environments, cysteine synthetase 1 (TtCsa1) was overexpressed in . The tolerance of /pET-28a- to cadmium was enhanced by expressing TtCsa1. Upon addition of cysteine, /pET-28a- generated more HS, which reacted with Cd to form CdS quantum dots (QDs), resulting in a stronger fluorescence signal. The UV-visible absorption and fluorescence spectra of the culture supernatant of /pET-28a- showed characteristic peaks corresponding to CdS QDs. Transmission Electron Microscopy (TEM) images confirmed that the formation of CdS QDs and their agglomeration in the cells. X-ray Diffraction Analysis (XRD) analysis further confirmed the presence of QDs and their crystalline nature. In rich medium, /pET-28a- achieved removal rates of 99.5%, 98.2%, 56.5%, and 49.4%, respectively, for Cd concentrations of 0.15, 0.3, 0.45, and 0.6 mM within 48 h. In simulated wastewater, /pET-28a- achieved removal rates of 99.4%, 94.3%, 90.1%, and 89.8%, respectively, for Cd concentrations of 0.3, 0.45, 0.6, and 0.75 mM within 12 h. These results demonstrate that overexpressing TtCsa1 in can significantly enhance its ability to biomineralize Cd in rich medium and simulated wastewater, which has potential applications in bioremediation of aquatic environments contaminated with heavy metals.
重金属镉会对水生生态系统造成严重污染。镉的生物矿化是多种微生物应对镉胁迫的重要生物学机制。为提高水生环境中微生物对镉的生物矿化能力，半胱氨酸合成酶1（TtCsa1）在[具体微生物名称未给出]中过表达。通过表达TtCsa1，[具体微生物名称未给出]/pET - 28a - 对镉的耐受性增强。添加半胱氨酸后，[具体微生物名称未给出]/pET - 28a - 产生更多的HS，其与Cd反应形成硫化镉量子点（QDs），导致更强的荧光信号。[具体微生物名称未给出]/pET - 28a - 培养上清液的紫外 - 可见吸收光谱和荧光光谱显示出与硫化镉量子点相对应的特征峰。透射电子显微镜（TEM）图像证实了硫化镉量子点在[具体微生物名称未给出]细胞中的形成及其团聚。X射线衍射分析（XRD）进一步证实了量子点的存在及其晶体性质。在丰富培养基中，对于0.15、0.3、0.45和0.6 mM的镉浓度，[具体微生物名称未给出]/pET - 28a - 在48小时内的去除率分别达到99.5%、98.2%、56.5%和49.4%。在模拟废水中，对于0.3、0.45、0.6和0.75 mM的镉浓度，[具体微生物名称未给出]/pET - 28a - 在12小时内的去除率分别达到99.4%、94.3%、90.1%和89.8%。这些结果表明，在[具体微生物名称未给出]中过表达TtCsa1可显著增强其在丰富培养基和模拟废水中对镉的生物矿化能力，这在重金属污染的水生环境生物修复中具有潜在应用价值。
