Botany and Microbiology Department, Faculty of Science, Benha University, Benha, 13518, Egypt.
Central Laboratory for Environmental Quality Monitoring, National Water Research Center, Elkanatir, 13621, Egypt.
Sci Rep. 2023 Jan 17;13(1):891. doi: 10.1038/s41598-023-27796-w.
Heavy metals, including lead, cause serious damage to human health and the surrounding environment. Natural biosorbents arise as environmentally friendly alternatives. In this study, two of the 41 isolates (8EF and 17OS) were the most efficient bacteria for growing on media supplemented with Pb (1000 mg/L). At high concentrations up to 2000 mg/L, the pioneer isolate 17OS exhibited remarkable resistance to multiheavy metals. This isolate was identified as Paenibacillus dendritiformis 17OS and deposited in GenBank under accession number ON705726.1. Design-Expert was used to optimize Pb metal removal by the tested bacteria. Results indicated that four of six variables were selected using a minimum-run resolution IV experimental design, with a significant affecting Pb removal. Temperature and Pb concentration were significant positive influences, whereas incubation period and agitation speed were significant negative ones. The tested strain modulated the four significant variables for maximum Pb removal using Box-Behnken design. The sequential optimization method was beneficial in increasing biosorption by 4.29%. Dead biomass of P. dendritiformis 17OS was embedded with polyethersulfone to get a hydrophilic adsorptive membrane that can separate Pb easily from aqueous solutions. SEM images and FT-IR analysis proved that the new biosorbent possesses a great structure and a lot of surface functional groups with a negative surface charge of - 9.1 mV. The removal rate of 200 mg/L Pb from water reached 98% using 1.5 g/L of the immobilized biosorbent. The adsorption isotherm studies were displayed to determine the nature of the reaction. The adsorption process was related to Freundlich isotherm which describes the multilayer and heterogeneous adsorption of molecules to the adsorbent surface. In conclusion, dead bacterial cells were immobilized on a polyether sulfone giving it the characteristics of a novel adsorptive membrane for the bioremediation of lead from wastewater. Thus this study proposed a new generation of adsorptive membranes based on polyethersulfone and dead bacterial cells.
重金属，包括铅，对人类健康和周围环境造成严重损害。天然生物吸附剂作为环保替代品应运而生。在这项研究中，从补充了 Pb（1000mg/L）的培养基中生长的 41 个分离株中有 2 个（8EF 和 17OS）是最有效的细菌。在高达 2000mg/L 的高浓度下，先驱分离株 17OS 对多种重金属表现出显著的抗性。该分离株被鉴定为枝动杆菌（Paenibacillus dendritiformis）17OS，并在 GenBank 中以 ON705726.1 的登录号进行了存储。采用 Design-Expert 优化测试细菌对 Pb 金属的去除。结果表明，在最小运行分辨率 IV 实验设计中选择了六个变量中的四个，这些变量对 Pb 去除有显著影响。温度和 Pb 浓度是显著的正影响因素，而培养期和搅拌速度是显著的负影响因素。该测试菌株使用 Box-Behnken 设计对四个显著变量进行了最大 Pb 去除的调节。序贯优化方法有利于生物吸附增加 4.29%。枝动杆菌（Paenibacillus dendritiformis）17OS 的死生物质嵌入聚醚砜中，以获得亲水性吸附膜，可使 Pb 容易从水溶液中分离出来。SEM 图像和 FT-IR 分析证明，新型生物吸附剂具有良好的结构和大量的表面官能团，表面电荷为-9.1mV。使用 1.5g/L 固定化生物吸附剂，从水中去除 200mg/L Pb 的去除率达到 98%。吸附等温线研究用于确定反应的性质。吸附过程与描述分子在吸附剂表面多层和不均匀吸附的 Freundlich 等温线有关。总之，死细菌细胞被固定在聚醚砜上，使其具有从废水中生物修复 Pb 的新型吸附膜的特性。因此，本研究提出了一种基于聚醚砜和死细菌细胞的新一代吸附膜。
