Genetic manipulation of cysH/cysJ in Citrobacter sp. XT1-2-2 enhanced cadmium immobilization by regulating metabolic pathways

文献类型： 外文期刊

第一作者： Liu, Zhudong

作者： Liu, Zhudong;Cheng, Wei;Li, Yilu;Shan, Shiping;Wu, Shandong;Wei, Xiaowu;Yang, Hua;Zhang, Min;Du, Dongxia;Liu, Zhudong;Cheng, Wei;Li, Yilu;Shan, Shiping;Wu, Shandong;Wei, Xiaowu;Yang, Hua;Zhang, Min;Du, Dongxia;Shan, Shiping

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关键词： Citrobacter sp. XT1-2-2; cadmium immobilization; CdS; sulfur metabolism; hydrogen sulfide

期刊名称：APPLIED AND ENVIRONMENTAL MICROBIOLOGY （ 影响因子：3.7； 五年影响因子：4.5 ）

ISSN： 0099-2240

年卷期： 2025 年

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收录情况： SCI

摘要： The Citrobacter sp. XT1-2-2 strain has emerged as a promising candidate for cadmium immobilization; however, the genetic basis underlying its sulfur-mediated bioremediation mechanisms remains inadequately understood. To address this gap, we concentrated on two pivotal genes, cysH and cysJ, within the sulfate assimilation pathway. We constructed Citrobacter sp. XT1-2-2-::APS and Citrobacter sp. XT1-2-2-::SiR strains with overexpression of cysH or cysJ for functional characterization. Transmission electron microscopy demonstrated a significant enhancement in the biosynthesis of CdS nanoparticles in both overexpression strains. This increase was attributed to the elevated production of hydrogen sulfide. Complementary physicochemical analyses, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and powder X-ray diffraction, further indicated that overexpression of cysH or cysJ modified functional groups on the surface and enhanced the efficiency of sulfur metabolism. Microcosm experiments demonstrated that the contents of Cd2+ in the roots, culms, leaves, and grains inoculated with overexpression strains were significantly lower than those observed in the wild-type strain. These findings establish a critical role for cysH/cysJ-mediated metabolic pathway regulation in cadmium immobilization. They provide a theoretical foundation for the exploration of novel bacterial-assisted techniques, marking a breakthrough in environmental biotechnology from fundamental research to the engineering application of genetically engineered bacteria.

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