Xu Pingping, Tu Xiaojie, An Zhengda, Mi Wujuan, Wan Dong, Bi Yonghong, Song Gaofei
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Toxics. 2024 Mar 31;12(4):262. doi: 10.3390/toxics12040262.
Cadmium ion (Cd) is a highly toxic metal in water, even at low concentrations. Microalgae are a promising material for heavy metal remediation. The present study investigated the effects of Cd on growth, photosynthesis, antioxidant enzyme activities, cell morphology, and Cd adsorption and accumulation capacity of the freshwater green alga . Experiments were conducted by exposing to varying concentrations of Cd for 96 h, assessing its tolerance and removal capacity towards Cd. The results showed that higher concentrations of Cd (>0.5 mg L) reduced pigment content, inhibited algal growth and electron transfer in photosynthesis, and led to morphological changes such as mitochondrial disappearance and chloroplast deformation. In this process, counteracted Cd toxicity by enhancing antioxidant enzyme activities, accumulating starch and high-density granules, and secreting extracellular polymeric substances. When the initial Cd concentration was less than or equal to 0.5 mg L, was able to efficiently remove over 95% of Cd from the environment through biosorption and bioaccumulation. However, when the initial Cd concentration exceeded 0.5 mg L, the removal efficiency decreased slightly to about 70%, with biosorption accounting for more than 60% of this process, emerging as the predominant mechanism for Cd removal. Fourier transform infrared correlation spectroscopy analysis indicated that the carboxyl and amino groups of the cell wall were the key factors in removing Cd. In conclusion, has considerable potential for the remediation of aquatic environments with Cd, providing algal resources for developing new microalgae-based bioremediation techniques for heavy metals.
镉离子（Cd）是水中一种剧毒金属，即使在低浓度下也是如此。微藻是一种很有前景的重金属修复材料。本研究调查了镉对淡水绿藻的生长、光合作用、抗氧化酶活性、细胞形态以及镉吸附和积累能力的影响。通过将其暴露于不同浓度的镉中96小时进行实验，评估其对镉的耐受性和去除能力。结果表明，较高浓度的镉（>0.5毫克/升）会降低色素含量，抑制藻类生长和光合作用中的电子传递，并导致线粒体消失和叶绿体变形等形态变化。在此过程中，通过增强抗氧化酶活性、积累淀粉和高密度颗粒以及分泌胞外聚合物来抵消镉的毒性。当初始镉浓度小于或等于0.5毫克/升时，能够通过生物吸附和生物积累从环境中高效去除超过95%的镉。然而，当初始镉浓度超过0.5毫克/升时，去除效率略有下降至约70%，其中生物吸附占该过程的60%以上，成为去除镉的主要机制。傅里叶变换红外相关光谱分析表明，细胞壁的羧基和氨基是去除镉的关键因素。总之，在镉污染的水环境修复方面具有相当大的潜力，为开发基于微藻的新型重金属生物修复技术提供了藻类资源。
