College of Life Science, Henan Agricultural University, Zhengzhou, 450002, China.
College of Forestry, Henan Agricultural University, Zhengzhou, 450002, China.
Chemosphere. 2019 Jun;225:200-208. doi: 10.1016/j.chemosphere.2019.03.027. Epub 2019 Mar 7.
Currently, Pb pollution has become a severe environmental problem and filamentous fungi hold a promising potential for the treatment of Pb-containing wastewater. The present study showed that the strain Pleurotus ostreatus ISS-1 had a strong ability to tolerate Pb at high concentration and reached a removal rate of 53.7% in liquid media. Pb was removed by extracellular biosorption, intracellular bioaccumulation by mycelia, or precipitation with extracellular oxalic acids. On the cellular level, Pb was mainly distributed in the cell wall, followed by vacuoles and organelles. Fourier transform infrared spectroscopy (FTIR) analysis indicated that hydroxyl, amides, carboxyl, and sulfhydryl groups provided binding sites for Pb. Furthermore, Pb was found on the cell surface in the form of PbS and PbCO through X-ray diffraction (XRD). Intracellular chelates such as thiol compounds and oxalic acid, as well as extracellular oxalic acid, might play an important role in the tolerance of Pb. In addition, isobaric tags for relative and absolute quantitation (iTRAQ) analysis showed that ATP-binding cassette (ABC) transporter, cytochrome P450, peroxisome, and the calcium signaling pathway might participate in both accumulation and detoxification of Pb. These results have successfully provided a basis for further developing Pb polluted water treatment technology by fungi.
目前，铅污染已成为一个严重的环境问题，丝状真菌在处理含铅废水方面具有很大的潜力。本研究表明，糙皮侧耳菌株 ISS-1 具有很强的耐高浓度铅的能力，在液体培养基中去除率达到 53.7%。铅通过细胞外的生物吸附、菌丝体的细胞内生物积累或细胞外草酸的沉淀来去除。在细胞水平上，铅主要分布在细胞壁上，其次是液泡和细胞器。傅里叶变换红外光谱（FTIR）分析表明，羟基、酰胺、羧基和巯基为 Pb 提供了结合位点。此外，通过 X 射线衍射（XRD）发现 Pb 以 PbS 和 PbCO 的形式存在于细胞表面。细胞内螯合物如硫醇化合物和草酸，以及细胞外草酸，可能在耐受 Pb 方面发挥重要作用。此外，相对和绝对定量同位素标记（iTRAQ）分析表明，三磷酸腺苷结合盒（ABC）转运蛋白、细胞色素 P450、过氧化物酶体和钙信号通路可能参与 Pb 的积累和解毒。这些结果为进一步开发真菌处理含铅废水的技术提供了依据。
