El-Beltagi Hossam S, Halema Asmaa A, Almutairi Zainab M, Almutairi Hayfa Habes, Elarabi Nagwa I, Abdelhadi Abdelhadi A, Henawy Ahmed R, Abdelhaleem Heba A R
Agricultural Biotechnology Department, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsa, Saudi Arabi.
Biochemistry Department, Faculty of Agriculture, Cairo University, Giza, Egypt.
Front Bioeng Biotechnol. 2024 Jan 8;11:1335854. doi: 10.3389/fbioe.2023.1335854. eCollection 2023.
Lead pollution of the environment poses a major global threat to the ecosystem. Bacterial bioremediation offers a promising alternative to traditional methods for removing these pollutants, that are often hindered by various limitations. Our research focused on isolating lead-resistant bacteria from industrial wastewater generated by heavily lead-containing industries. Eight lead-resistant strains were successfully isolated, and subsequently identified through molecular analysis. Among these, FACU6 emerged as a particularly promising candidate, demonstrating an efficient lead removal rate of 83.4% and a remarkable lead absorption capacity of 571.9 mg/g dry weight. Furthermore, FACU6 displayed a remarkable a maximum tolerance concentration (MTC) for lead reaching 3,000 mg/L. To further investigate the morphological changes in FACU6 in response to lead exposure, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed. These analyses revealed significant lead adsorption and intracellular accumulation in treated bacteria in contrast to the control bacterium. Whole-genome sequencing was performed to gain deeper insights into . lead resistance mechanisms. Structural annotation revealed a genome size of 4,856,454 bp, with a G + C content of 55.06%. The genome encodes 4,655 coding sequences (CDS), 75 tRNA genes, and 4 rRNA genes. Notably, genes associated with heavy metal resistance and their corresponding regulatory elements were identified within the genome. Furthermore, the expression levels of four specific heavy metal resistance genes were evaluated. Our findings revealed a statistically significant upregulation in gene expression under specific environmental conditions, including pH 7, temperature of 30°C, and high concentrations of heavy metals. The outstanding potential of FACU6 as a source of diverse genes related to heavy metal resistance and plant growth promotion makes it a valuable candidate for developing safe and effective strategies for heavy metal disposal.
环境中的铅污染对生态系统构成了重大的全球威胁。细菌生物修复为去除这些污染物的传统方法提供了一种有前景的替代方案，传统方法常常受到各种限制的阻碍。我们的研究重点是从含铅量高的行业产生的工业废水中分离抗铅细菌。成功分离出八株抗铅菌株，随后通过分子分析进行鉴定。其中，FACU6成为一个特别有前景的候选菌株，其铅去除率高达83.4%，铅吸收能力显著，为571.9毫克/克干重。此外，FACU6对铅的最大耐受浓度（MTC）达到3000毫克/升。为了进一步研究FACU6在铅暴露下的形态变化，采用了扫描电子显微镜（SEM）和透射电子显微镜（TEM）。这些分析表明，与对照细菌相比，处理后的细菌中有明显的铅吸附和细胞内积累。进行全基因组测序以更深入地了解铅抗性机制。结构注释显示基因组大小为4856454碱基对，G + C含量为55.06%。该基因组编码4655个编码序列（CDS）、75个tRNA基因和4个rRNA基因。值得注意的是，在基因组中鉴定出了与重金属抗性相关的基因及其相应的调控元件。此外，评估了四个特定重金属抗性基因的表达水平。我们的研究结果表明，在特定环境条件下，包括pH值为7、温度为30°C和高浓度重金属条件下，基因表达在统计学上有显著上调。FACU6作为与重金属抗性和植物生长促进相关多种基因的来源，具有突出的潜力，使其成为开发安全有效的重金属处理策略的有价值候选者。
