Key Laboratory of Bio-Resource and Eco-Evironment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
Key Laboratory of Bio-Resource and Eco-Evironment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, PR China.
J Hazard Mater. 2020 Dec 5;400:123116. doi: 10.1016/j.jhazmat.2020.123116. Epub 2020 Jun 15.
Microbial induced carbonate precipitation (MICP) is known as a significant process for remediating heavy metals contaminated environment. In this study, a novel Cd-resistant ureolytic bacteria was isolated and identified as Enterobacter sp. Its performances for immobilizing Cd in solution and soil were systematically discussed at different treatment conditions. Results showed that initial pH and Cd concentration were important parameters to influence Cd removal rate. The maximal Cd removal rate in solution reached 99.50 % within 7 days by MICP. The precipitation produced in Cd removal process were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometer to understand the removal mechanism. Analyses showed that Cd removal mechanism of CJW-1 was predominately via biominerals including calcites and vaterites to absorb Cd. Cd immobilization tests demonstrated that the highest Cd-immobilization rate in soil could reach 56.10 %. Although all treatments contribute to soil pH, fertility, and enzyme activities improvement, oyster shell wastes (OS) had a better effect on soil cation exchange capacity. All treatments had negative effects on soil respiration and bacterial community, but OS can alleviate such adverse influence. Our results emphasized that Cd-resistant ureolytic bacteria strain CJW-1 combined with OS had excellent ability and reuse value to remediate Cd-contaminated environment.
微生物诱导碳酸钙沉淀（MICP）被认为是修复重金属污染环境的重要过程。本研究从受重金属污染的土壤中筛选得到一株能够耐受镉的产脲酶细菌，鉴定为肠杆菌属（Enterobacter sp.），并系统研究了其在不同处理条件下固定溶液和土壤中镉的性能。结果表明，初始 pH 值和镉浓度是影响镉去除率的重要参数。通过 MICP，在 7 天内溶液中镉的最大去除率达到 99.50%。通过 X 射线衍射、扫描电子显微镜和能谱仪对去除过程中产生的沉淀进行了表征，以了解去除机制。分析表明，CJW-1 的镉去除机制主要是通过生物矿化作用，包括方解石和文石来吸附镉。镉固定化试验表明，土壤中镉的最大固定化率可达 56.10%。虽然所有处理都有助于提高土壤 pH 值、肥力和酶活性，但蚝壳废弃物（OS）对土壤阳离子交换能力的改善效果更好。所有处理均对土壤呼吸和细菌群落产生负面影响，但 OS 可以减轻这种不利影响。我们的研究结果强调了耐镉产脲酶细菌 CJW-1 与 OS 结合具有修复镉污染环境的优异能力和再利用价值。
