Department of Environmental Engineering, University of Seoul, Seoul 02504, South Korea.
PG & Research Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal 637501, Tamil Nadu, India.
Ecotoxicol Environ Saf. 2019 Jun 15;174:699-705. doi: 10.1016/j.ecoenv.2019.03.034. Epub 2019 Mar 14.
In the present study, we investigated the role of calcite, i.e., microbiologically-induced precipitate by ureolytic Trichoderma sp. MG, in remediation of soils contaminated with arsenic (As) and lead (Pb). The fungus tolerates high concentrations of As (500 mg/L) and Pb (650 mg/L). The effects of three factors, i.e., urea concentration, CaCl concentration and pH, on urease production and bio-mineralization of As and Pb were investigated using Box-Behnken design. The maximum urease production (920 U/mL) and metal removal efficiency (68% and 59% for Pb and AS, respectively) were observed in the medium containing urea of 300 mM and CaCl of 75 mM at pH 9.0. Fourier transform infrared spectroscopy result revealed the formation of metal carbonates by the isolate MG. Sequential extraction of metals revealed that the carbonate fractions of As and Pb were increased to 46.4% and 42.4% in bioremediated soil, whereas in control they were 35.5% and 32.5%, respectively. The X-ray powder diffraction result further confirmed the role of calcite precipitate in bioremediation of As- and Pb-contaminated soils. The results points out that the microbiologically-induced calcite precipitation is a feasible, eco-friendly technology for the bioremediation of As- and Pb-contaminated sites.
在本研究中，我们研究了方解石（即由产脲酶的 Trichoderma sp. MG 诱导产生的微生物沉淀）在修复砷（As）和铅（Pb）污染土壤中的作用。该真菌可耐受高浓度的 As（500mg/L）和 Pb（650mg/L）。采用 Box-Behnken 设计研究了尿素浓度、CaCl2 浓度和 pH 值三个因素对产脲酶和生物矿化 As 和 Pb 的影响。在含有 300mM 尿素和 75mM CaCl2 的 pH 9.0 培养基中，观察到最大的脲酶产量（920U/mL）和金属去除效率（Pb 和 As 分别为 68%和 59%）。傅里叶变换红外光谱结果表明，MG 分离物形成了金属碳酸盐。金属的连续提取表明，生物修复土壤中 As 和 Pb 的碳酸盐分数分别增加到 46.4%和 42.4%，而对照中分别为 35.5%和 32.5%。X 射线粉末衍射结果进一步证实了方解石沉淀在生物修复 As 和 Pb 污染土壤中的作用。结果表明，微生物诱导的方解石沉淀是一种可行的、环保的生物修复 As 和 Pb 污染场地的技术。
