In the present study, native bacterial strains isolated from abandoned gold mine and Chromobacterium violaceum (MTCC-2656) were applied for bioleaching of metals from waste printed circuit boards (WPCBs). Toxicity assessment and dose–response analysis of WPCBs showed EC₅₀ values of 128.9, 98.7, and 90.8 g/L for Bacillus sp. SAG3, Bacillus megaterium SAG1 and Lysinibacillus sphaericus SAG2, respectively, whereas, for C. violaceum EC₅₀ was 83.70 g/L. This indicates the viable operation range and technological feasibility of metals bioleaching from WPCBs using mine isolates. The influencing factors such as pH, pulp density, temperature, and precursor molecule (glycine) were optimized by one-factor at a time method (OFAT). The maximum metal recovery occurred at an initial pH of 9.0, a pulp density of 10 g/L, a temperature of 30 °C and a glycine concentration of 5 g/L, except for L. sphaericus which showed optimum activity at initial pH of 8.0. Under optimal conditions the metals recovery of Cu and Au from WPCBs were recorded as 87.5 ± 8% and 73.6 ± 3% for C. violaceum and 72.7 ± 5% and 66.6 ± 6% for B. megaterium, respectively. Kinetic modeling results showed that the data was best described by first order reaction kinetics, where the rate of metal solubilization from WPCBs depended upon microbial lixiviant production. This is the first report on bioleaching of metals from e-waste using bacterial isolates from the gold mine of Solan, HP. Our study demonstrated the potential of bioleaching for resource recovery from WPCBs dust, aimed to be disposed at landfills, and its effectiveness in extraction of elements those are at high supply risk and demand.

在本研究中，从废弃的金矿和紫色色杆菌(MTCC-2656) 中分离出的天然细菌菌株被用于生物浸出废印刷电路板 (WPCB) 中的金属。WPCB 的毒性评估和剂量反应分析显示芽孢杆菌的 EC ₅₀值为128.9、98.7和 90.8 g/L 。SAG3、巨大芽孢杆菌SAG1 和球形赖氨酸芽孢杆菌SAG2，而对于C. violaceum EC ₅₀为 83.70 克/升。这表明使用矿山分离物从 WPCB 中生物浸出金属的可行操作范围和技术可行性。pH、纸浆密度、温度和前体分子（甘氨酸）等影响因素通过一次单因素法（OFAT）进行了优化。最大金属回收发生在初始 pH 为 9.0、纸浆密度为 10 g/L、温度为 30 °C 和甘氨酸浓度为 5 g/L 时，除了球形乳杆菌在初始 pH 为8.0。在最佳条件下，从 WPCB 中回收的铜和金的金属回收率分别为C. violaceum的 87.5 ± 8% 和 73.6 ± 3%，以及巨大芽孢杆菌的 72.7 ± 5% 和 66.6 ± 6%， 分别。动力学建模结果表明，数据最好通过一级反应动力学来描述，其中 WPCB 的金属溶解速率取决于微生物浸出剂的产生。这是关于使用来自 HP Solan 金矿的细菌分离物从电子废物中生物浸出金属的第一份报告。我们的研究证明了生物浸出从 WPCB 粉尘中回收资源的潜力，旨在处理垃圾填埋场，以及它在提取供应风险和需求高的元素方面的有效性。