Effect of Ginkgo biloba leaves on the removal efficiency of Cr(VI) in soil and its underlying mechanism

文献类型： 外文期刊

第一作者： Xu, Hefeng

作者： Xu, Hefeng;Fan, Yanling;Liu, Zengjun;Yang, Shuo;Xia, Xu

作者机构：

关键词： Ginkgo biloba leaves; Cr(VI); Bacterial community structure; Removal mechanism; X-ray absorption near -edge structure (XANES)

期刊名称：ENVIRONMENTAL RESEARCH （ 影响因子：8.431； 五年影响因子：8.399 ）

ISSN： 0013-9351

年卷期： 2023 年 216 卷

页码：

收录情况： SCI

摘要： Cr(VI) is a toxic, teratogenic, and carcinogenic heavy metal element in soil that poses major ecological and human health risks. In this study, microcosm tests combined with X-ray absorption near-edge spectra (XANES) and 16Sr DNA amplification techniques were used to explore the effect of Ginkgo biloba leaves on the removal efficiency of Cr(VI) in soil and its underlying mechanism. Ginkgo biloba leaves had a favorable remediation effect on soil varying in Cr(VI) contamination levels, and the optimal effect was observed when 5% Ginkgo biloba leaves were added. The occurrence state of Cr(VI) in soil before and after the addition of Ginkgo biloba leaves was analyzed by XANES, which revealed that Cr(VI) was fully converted to the more biologically innocuous Cr(III), and the hydroxyl-containing quercetin in Ginkgo biloba leaves was one of the primary components mediating this reduction reaction. The Cr(VI) content was significantly lower in non-sterilized soil than in sterilized soil, sug-gesting that soil microorganisms play a key role in the remediation process. The addition of Ginkgo biloba leaves decreased the alpha-diversity and altered the beta-diversity of the soil bacterial community. Actinobacteria was the dominant phylum in the soil remediated by Ginkgo biloba leaves; four genera of Cr(VI)-reducing bacteria were also enriched, including Agrococcus, Klebsiella, Streptomyces, and Microbacterium. Functional gene abundances predicted by PICRUST indicated that the expression of glutathione synthesis genes was substantially up -regulated, which might be the main metabolic pathway underlying the mitigation of Cr(VI) toxicity in soil by Cr(VI)-reducing bacteria. In sum, Ginkgo biloba leaves can effectively remove soil Cr(VI) and reduce Cr(VI) to Cr (III) via quercetin in soil, which also functions as a carbon source to drive the production of glutathione via Cr (VI)-reducing bacteria and mitigate Cr(VI) toxicity. The findings of this study elucidate the chemical and mi-crobial mechanisms of Cr(VI) removal in soil by Ginkgo biloba leaves and provide insights that could be used to enhance the remediation of Cr(VI)-contaminated soil.

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