Traditional fermented foods are important sources of probiotics, which attract intensive attentions because of their beneficial effects. The potential of probiotic strains to remove heavy metals have also aroused interest from researchers. In this study, the ability of lactic acid bacteria (LAB) isolated from various fermented foods to removal lead (Pb) was tested, and strains with high removal efficiency were selected and characterized by the use of scanning electron microscope equipped with energy dispersive spectrometer (SEM–EDS), Fourier transform infrared spectrometer (FTIR) and X-ray photoelectron spectroscopy (XPS) to investigate the mechanism of lead removal. Two selected strains, identified as Enterococcus faecium DUTYH_16120012 and Enterococcus sp. DUTYH_16120026, were found capable of removing Pb²⁺ efficiently from MRS broth. Results indicated that initial pH, Pb²⁺ concentration and growing temperature were important factors affecting lead removal, which might be attributed to the effects of these factors on bacterial growth and physiology. The cell wall played a major role, contributing 80.58 ± 1.65%, in Pb²⁺ removal by bacterial cells. SEM–EDS and XPS analysis implied that possible chemical compositions of the yellow–brown deposits observed on the cell pellets grown in presence of lead were PbO₂ and PbO. FTIR analysis indicated that some functional groups (–OH, –C=O, –N–H, –C–N) were involved in the Pb²⁺ removal process. The isolated strains demonstrated a potential for lead removal, but further study was needed to reveal the detailed mechanism by which the selected strain removes lead from the growing environment.

中文翻译：

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酸菜肠球菌菌株的分离和鉴定及潜在的去铅潜力

传统的发酵食品是益生菌的重要来源，由于其有益的作用，引起了广泛的关注。益生菌菌株去除重金属的潜力也引起了研究人员的兴趣。在这项研究中，测试了从各种发酵食品中分离出的乳酸菌（LAB）去除铅（Pb）的能力，并选择了具有高去除效率的菌株，并使用配备了能量分散光谱仪的扫描电子显微镜（ SEM-EDS），傅立叶变换红外光谱仪（FTIR）和X射线光电子能谱（XPS）来研究铅去除的机理。选定的两个菌株分别为粪肠球菌DUTYH_16120012和肠球菌sp。发现DUTYH_16120026能够有效地从MRS肉汤中除去Pb ²⁺。结果表明，初始pH，Pb ²⁺浓度和生长温度是影响铅去除的重要因素，这可能归因于这些因素对细菌生长和生理的影响。细胞壁在细菌细胞去除Pb ^2+中起主要作用，占80.58±1.65％。SEM-EDS和XPS分析表明，在铅存在下生长的细胞沉淀上观察到的黄棕色沉积物可能的化学成分是PbO ₂和PbO。FTIR分析表明，某些官能团（–OH，–C = O，–NH–H，–C–N）与Pb ^2+有关删除过程。分离出的菌株显示出去除铅的潜力，但是需要进一步的研究来揭示所选菌株从生长环境中去除铅的详细机理。