Scholarlink

<p>Microbial-induced carbonate precipitation is a promising biotechnology that utilizes microorganisms to precipitate carbonate minerals, which can be regarded as an effective method for remediating heavy metal contamination. However, there are still challenges to overcome, such as optimizing the technique for different environmental conditions and improving its efficiency. A microcosm experiment compared two bacterial inoculation strategies—fermentation broth (BN<sub>fb</sub>) and centrifuged bacterial suspension (B<sub>cs</sub>)—applied at five dosages (0–12&#xa0;mL per 200&#xa0;g of soil) across four Cd gradients (1–20&#xa0;mg&#xa0;kg<sup>−1</sup>). BN<sub>fb</sub> achieved a 26.07–41.84% reduction in exchangeable Cd (Exc-Cd) compared to controls, while carbonate-bound Cd (Carb-Cd) increased by 36.13–49.90% under BN<sub>fb</sub> and 24.34–32.71% under B<sub>cs</sub> (<i>p </i>&lt; 0.01). Optimal efficacy was observed at 6&#xa0;mL of BN<sub>fb</sub> per 200&#xa0;g of soil, corresponding to 2.58 × 10<sup>10</sup> bacterial cells. BN<sub>fb</sub> significantly elevated soil urease activity (<i>p</i> &lt; 0.001) and boosted key carbon-cycling enzymes: <i>β</i>-N-acetylglucosaminase (NAG), <i>β</i>-xylosidase (BX), and β-glucosidase (BG) by up to 135.92, 48.30, and 19.57%, respectively. High-throughput sequencing revealed BN<sub>fb</sub> increased the relative abundance of <i>Sphingomonas</i>, <i>Bacillus</i>, and <i>Lysobacter</i> while reducing bacterial alpha diversity (Chao1 and Shannon indices, <i>p</i> &lt; 0.05) but enhancing community uniformity. Chemoheterotrophic and chitinolytic bacteria dominated, supporting Cd immobilization and wheat growth. BN<sub>fb</sub> improved wheat chlorophyll (SPAD) and total nitrogen (TN) content (<i>p</i> &lt; 0.001), whereas B<sub>cs</sub> showed no mitigation under Cd stress. These findings validate BN<sub>fb</sub> as a potent, eco-friendly strategy for Cd remediation, with clear dosage-dependent efficacy and microbial community shifts. It is recommended that 2.58 × 10<sup>10</sup> bacterial cells from <i>B. pasteurii</i> fermentation be introduced into each 200&#xa0;g of Cd-contaminated soil to achieve effective remediation. Overall, MICP represents a versatile and environmentally sustainable strategy for addressing heavy metal contamination in soils, with continued research efforts focusing on enhancing its efficiency and broadening its applicability.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Remediation of a floodplain soil contaminated by different gradients of Cd, applying MICP technique

  • 期刊论文

  • 发表日期：

    2026年2月8日

查看全文
  • Zhiguang Han,
  • Jing Wang,
  • Jianwei Zhang,
  • Haoran Gui,
  • Junqiang Zheng

摘要

Microbial-induced carbonate precipitation is a promising biotechnology that utilizes microorganisms to precipitate carbonate minerals, which can be regarded as an effective method for remediating heavy metal contamination. However, there are still challenges to overcome, such as optimizing the technique for different environmental conditions and improving its efficiency. A microcosm experiment compared two bacterial inoculation strategies—fermentation broth (BNfb) and centrifuged bacterial suspension (Bcs)—applied at five dosages (0–12 mL per 200 g of soil) across four Cd gradients (1–20 mg kg−1). BNfb achieved a 26.07–41.84% reduction in exchangeable Cd (Exc-Cd) compared to controls, while carbonate-bound Cd (Carb-Cd) increased by 36.13–49.90% under BNfb and 24.34–32.71% under Bcs (p < 0.01). Optimal efficacy was observed at 6 mL of BNfb per 200 g of soil, corresponding to 2.58 × 1010 bacterial cells. BNfb significantly elevated soil urease activity (p < 0.001) and boosted key carbon-cycling enzymes: β-N-acetylglucosaminase (NAG), β-xylosidase (BX), and β-glucosidase (BG) by up to 135.92, 48.30, and 19.57%, respectively. High-throughput sequencing revealed BNfb increased the relative abundance of Sphingomonas, Bacillus, and Lysobacter while reducing bacterial alpha diversity (Chao1 and Shannon indices, p < 0.05) but enhancing community uniformity. Chemoheterotrophic and chitinolytic bacteria dominated, supporting Cd immobilization and wheat growth. BNfb improved wheat chlorophyll (SPAD) and total nitrogen (TN) content (p < 0.001), whereas Bcs showed no mitigation under Cd stress. These findings validate BNfb as a potent, eco-friendly strategy for Cd remediation, with clear dosage-dependent efficacy and microbial community shifts. It is recommended that 2.58 × 1010 bacterial cells from B. pasteurii fermentation be introduced into each 200 g of Cd-contaminated soil to achieve effective remediation. Overall, MICP represents a versatile and environmentally sustainable strategy for addressing heavy metal contamination in soils, with continued research efforts focusing on enhancing its efficiency and broadening its applicability.