He Xiaoman, Xiao Weiwei, Zeng Jiayuan, Tang Jie, Wang Lin
College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, 410008, China.
J Environ Manage. 2023 Jun 15;336:117641. doi: 10.1016/j.jenvman.2023.117641. Epub 2023 Mar 1.
Arsenite [As(III)] oxidizing bacteria have been widely studied for their detoxification ability through transforming As(III) into arsenate [As(V)]. However, few was focused on removal capacity of arsenic (As). In the current study, As(III) oxidation accompanied with removal of total As was observed in Pseudomonas sp. SMS11. The biosorption (unbinding and surface binding) and bioaccumulation (intracellular uptake) of As by the cells were investigated. Biosorption isotherm was defined adequately by Langmuir and Freundlich models. Biosorption kinetics was recommended by pseudo second-order model. For comparison, the bacteria were inoculated in pure water or culture media amended with different concentrations of As(III) to evaluate the remediation capacity without or with bacterial growth. After removing unbound As, surface bound and intracellular As were sequentially separated using EDTA elution and acidic extraction from bacterial cells. Without bacterial growth, oxidation of As(III) was retarded and the maximum values of surface bound and intracellular As were 4.8 and 10.5 mg/g, respectively. Efficient oxidation and high adsorption capacity were observed after bacterial growth. The surface bound and intracellular As achieved up to 555.0 and 2421.5 mg/g, respectively. Strain SMS11 exhibited great accumulation capacity of As in aqueous solutions, indicating potential application in detoxification and removal of As(III) contamination. The results also suggested that bioremediation via bacteria should be based on living cells and bacterial growth rate.
亚砷酸盐[As(III)]氧化细菌因其通过将As(III)转化为砷酸盐[As(V)]的解毒能力而受到广泛研究。然而，很少有研究关注砷（As）的去除能力。在本研究中，在假单胞菌属SMS11中观察到As(III)氧化伴随着总As的去除。研究了细胞对As的生物吸附（解吸和表面结合）和生物累积（细胞内摄取）。Langmuir和Freundlich模型充分定义了生物吸附等温线。伪二级模型推荐了生物吸附动力学。为了进行比较，将细菌接种在纯水或添加不同浓度As(III)的培养基中，以评估有无细菌生长时的修复能力。去除未结合的As后，使用EDTA洗脱和酸性提取从细菌细胞中依次分离表面结合的As和细胞内的As。在没有细菌生长的情况下，As(III)的氧化受到抑制，表面结合的As和细胞内的As的最大值分别为4.8和10.5 mg/g。细菌生长后观察到高效氧化和高吸附能力。表面结合的As和细胞内的As分别达到555.0和2421.5 mg/g。菌株SMS11在水溶液中表现出很强的As累积能力，表明其在解毒和去除As(III)污染方面具有潜在应用价值。结果还表明，通过细菌进行生物修复应基于活细胞和细菌生长速率。
