College of Resources and Environment, Shanxi Agricultural University, Taigu, 030801, Shanxi, People's Republic of China.
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
Appl Microbiol Biotechnol. 2021 Mar;105(5):2171-2179. doi: 10.1007/s00253-021-11155-8. Epub 2021 Feb 9.
Pollution with the heavy metal cadmium (Cd) is a global problem. Cadmium adversely affects living organisms, highlighting the need to develop new methods for removal of this pollutant from the environment. In this study, we used a novel biomaterial based on calcium-crosslinked alginate-encapsulated bacteria to precipitate Cd in polluted water. Our results show that calcium-crosslinked alginate-encapsulated bacteria effectively removed Cd ions from cadmium-polluted water. Approximately 100% of Cd ions were removed by 10 g (wet weight) of this biomaterial when the loading concentration of Cd reached 1 mM in a volume of 50 ml water. During this process, a CdS nanoparticle, showing good crystallinity in the quantum range, was simultaneously produced. To validate the activity and stability of this biomaterial, we measured cysteine desulfhydrase activity in the stored biomaterial and whether this biomaterial could be recycled. The encapsulated bacteria maintained catalytic activity for at least 2 weeks. The capsules were easily regenerated and possessed good recyclability. Our results indicated that calcium-crosslinked alginate-encapsulated bacteria are suitable for depletion of Cd in polluted water and for production of CdS nanoparticles. These calcium-crosslinked alginate-encapsulated bacteria are safe for biological manipulation and can be widely used to produce CdS nanoparticles during bioremediation of Cd-polluted water. KEY POINTS: • Calcium-crosslinked alginate-encapsulated bacteria can effectively precipitate Cd in water coupled with production of CdS quantum dots. • The encapsulated bacteria maintained catalytic activity for at least 2 weeks. • The capsules were easily regenerated and possessed good recyclability.
重金属镉（Cd）污染是一个全球性问题。镉会对生物体造成不良影响，这凸显了开发从环境中去除这种污染物的新方法的必要性。在这项研究中，我们使用了一种基于钙交联海藻酸钠包封细菌的新型生物材料来沉淀受污染水中的 Cd。我们的结果表明，钙交联海藻酸钠包封细菌有效地从镉污染水中去除 Cd 离子。当负载浓度为 1mM 时，10g（湿重）这种生物材料可去除约 100%的 Cd 离子，体积为 50ml 的水。在此过程中，同时产生了具有良好量子范围结晶度的 CdS 纳米粒子。为了验证这种生物材料的活性和稳定性，我们测量了储存生物材料中的半胱氨酸脱硫酶活性，以及这种生物材料是否可以回收利用。包封的细菌至少保持 2 周的催化活性。胶囊易于再生，具有良好的可回收性。我们的结果表明，钙交联海藻酸钠包封细菌适合用于耗尽受污染水中的 Cd，并用于生产 CdS 纳米粒子。这些钙交联海藻酸钠包封细菌可安全进行生物操作，并可广泛用于生物修复 Cd 污染水时生产 CdS 纳米粒子。关键点：
钙交联海藻酸钠包封细菌可有效沉淀水中的 Cd，并同时生产 CdS 量子点。
包封的细菌至少保持 2 周的催化活性。
胶囊易于再生，具有良好的可回收性。
