Exploring the synergistic interplay of sulfur metabolism and electron transfer in Cr(VI) and Cd(II) removal by Clostridium thiosulfatireducens: Genomic and mechanistic insights.
Exploring the synergistic interplay of sulfur metabolism and electron transfer in Cr(VI) and Cd(II) removal by Clostridium thiosulfatireducens: Genomic and mechanistic insights.
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DOI：
10.1016/j.chemosphere.2024.141289
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发表时间：
2024-01
期刊：
影响因子：
8.8
通讯作者：
Suya Ma;Shuaixian Mao;Jinshuai Shi;Jiacheng Zou;Jiale Zhang;Yingchao Liu;Xinrong Wang;Zizhen Ma;Caihong Yu
中科院分区：
文献类型：
--
作者：
Suya Ma;Shuaixian Mao;Jinshuai Shi;Jiacheng Zou;Jiale Zhang;Yingchao Liu;Xinrong Wang;Zizhen Ma;Caihong Yu
本文报道了一种硫酸盐还原菌--硫代硫酸还原梭菌（Clostridiumthiosulfatireducens，CT），并研究了其对Cr（VI）和Cd（II）的去除性能和机理。值得注意的是，该菌株中不存在dsrAB基因，但该菌株能够产生硫化物。当Cr（VI）浓度为25 mg/L时，CT对Cr（VI）的转化率为84.24%，当Cd（II）浓度为28 mg/L时，CT对Cd（II）的转化率为94.19%.其基因组全长为6，106，624 bp，由一条染色体组成。染色体GC含量为29.65%。CT菌去除重金属的机理主要包括生物吸附、电子传递和氧化还原，其中还原结合S2−沉淀是主要途径。产物表征结果表明，吸附后主要形成离子晶体和沉淀物（CdS、Cd（OH）2、Cr（OH）3、Cr2 O3）。全基因组技术表明，Cr（VI）和Cd（II）的清除CT在很大程度上依赖于硫酸盐转运，硫代谢，能量代谢在一定程度上。此外，与ATP结合、电子载体活性、转运蛋白基因、DNA修复等相关的基因也是提高CT菌株重金属抗性和转化能力的重要因素。Fe-S循环和抗ROS系统都可以增强电子转移活性，从而减缓重金属对微生物的损害。本研究填补了对CT基本性质和重金属转化机理认识上的差距。
In this study, a sulfate-reducing bacterium,Clostridiumthiosulfatireducens(CT) was reported and the performance and removal mechanism of Cr(VI) and Cd(II) removal were investigated. It is noteworthy that the dsrAB gene is absent in this strain, but the strain is capable of producing sulfide. The conversion rate of Cr(VI) by CT was 84.24 % at a concentration of 25 mg/L, and the conversion rate of Cd(II) was 94.19 % at a concentration of 28 mg/L. The complete genome is 6,106,624 bp and the genome consisted of a single chromosome. The GC content of the chromosomes was 29.65 %. The mechanism of heavy metal removal by CT bacteria mainly includes biosorption, electron transfer and redox, with reduction combined with S2−precipitation as the main pathway. The product characterization results showed that the formation of mainly ionic crystals and precipitates (CdS, Cd(OH)2, Cr(OH)3, Cr2O3) after adsorption. Genome-wide techniques have shown that the clearance of Cr(VI) and Cd(II) by CT is largely dependent on sulfate transport, sulfur metabolism, and energy metabolism to some extent. In addition, genes related to ATP binding, electron carrier activity, transporter protein genes, and DNA repair are also important factors to improve the heavy metal resistance and transformation ability of CT strains. Both the Fe–S cycle and the ROS-resistant system can enhance the electron transfer activity and thus slow down the damage of heavy metals to microorganisms. This study fills the gap in the understanding of the basic properties and heavy metal transformation mechanism of CT.