Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Himachal Pradesh, Waknaghat, Solan, 173234, India.
Department of Microbiology, Guru Nanak Dev University, Amritsar, Punjab, 143005, India.
Biometals. 2021 Oct;34(5):1043-1058. doi: 10.1007/s10534-021-00326-9. Epub 2021 Jul 2.
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 EC 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 EC 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，从废弃金矿和紫色杆菌（MTCC-2656）中分离出的本土细菌菌株被用于从废印刷电路板（WPCB）中浸出金属。对 WPCB 的毒性评估和剂量反应分析表明，芽孢杆菌 SAG3、巨大芽孢杆菌 SAG1 和球形赖氨酸芽孢杆菌 SAG2 的 EC 值分别为 128.9、98.7 和 90.8 g/L，而对于紫色杆菌，EC 值为 83.70 g/L。这表明使用矿山分离物从 WPCB 中浸出金属具有可行的操作范围和技术可行性。通过单因素法（OFAT）优化了 pH 值、浆体密度、温度和前体分子（甘氨酸）等影响因素。最大金属回收率出现在初始 pH 值为 9.0、浆体密度为 10 g/L、温度为 30°C 和甘氨酸浓度为 5 g/L 的条件下，除球形赖氨酸芽孢杆菌在初始 pH 值为 8.0 时表现出最佳活性外。在最佳条件下，紫色杆菌从 WPCB 中回收的 Cu 和 Au 分别为 87.5±8%和 73.6±3%，巨大芽孢杆菌分别为 72.7±5%和 66.6±6%。动力学模型结果表明，数据最符合一级反应动力学，金属从 WPCB 中的溶解速率取决于微生物浸出剂的产生。这是首次报道使用来自喜马偕尔邦索兰金矿的细菌分离物从电子废物中浸出金属。我们的研究证明了从 WPCB 粉尘中生物浸出回收资源的潜力，这些粉尘旨在在垃圾填埋场中处理，并且它在提取高供应风险和高需求元素方面具有有效性。
