Behavior and Mechanism of Cesium Biosorption from Aqueous Solution by Living Synechococcus PCC7002

Microorganisms

Fengzheng Gao¹  Jun Ye²  Danchan Liu²  Tao Ma²  Li Shen³  Xueling Wu³  Weimin Zeng³  Yuandong Liu³  Runlan Yu³  Zhaojing Yu³  Hongsheng Chai³  Jiaokun Li³ 

[1] College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China;Hunan Qingzhiyuan Environmental Protection Technology Co, Ltd., Changsha 410000, China;School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;

关键词: Biosorption;    Synechococcus PCC7002;    Cs;    EPS;   

DOI  :  10.3390/microorganisms8040491

来源: DOAJ

【 摘 要 】

Many efforts have focused on the adsorption of metals from contaminated water by microbes. Synechococcus PCC7002, a major marine cyanobacteria, is widely applied to remove metals from the ocean’s photic zone. However, its ability to adsorb cesium (Cs) nuclides has received little attention. In this study, the biosorption behavior of Cs(I) from ultrapure distilled water by living Synechococcus PCC7002 was investigated based on kinetic and isotherm studies, and the biosorption mechanism was characterized by Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and three-dimensional excitation emission matrix fluorescence spectroscopy. Synechococcus PCC7002 showed extremely high tolerance to Cs ions and its minimal inhibitory concentration was 8.6 g/L. Extracellular polymeric substances (EPS) in Synechococcus PCC7002 played a vital role in this tolerance. The biosorption of Cs by Synechococcus PCC7002 conformed to a Freundlich-type isotherm model and pseudo-second-order kinetics. The binding of Cs(I) was primarily attributed to the extracellular proteins in EPS, with the amino, hydroxyl, and phosphate groups on the cell walls contributing to Cs adsorption. The biosorption of Cs involved two mechanisms: Passive adsorption on the cell surface at low Cs concentrations and active intracellular adsorption at high Cs concentrations. The results demonstrate that the behavior and mechanism of Cs adsorption by Synechococcus PCC7002 differ based on the Cs ions concentration.

【 授权许可】

Unknown