期刊
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
卷 8, 期 -, 页码 -出版社
FRONTIERS MEDIA SA
DOI: 10.3389/fbioe.2020.00528
关键词
constraint-based modeling; bioleaching; cyanide; chemically-defined medium; genome-scale metabolic model
资金
- Tarbiat Modares University [IG-39701]
- Novo Nordisk Foundation [NNF10CC1016517]
- Biotechnology Development Council of the Islamic Republic of Iran [970301]
With the constant accumulation of electronic waste, extracting precious metals contained therein is becoming a major challenge for sustainable development.Bacillus megateriumis currently one of the microbes used for the production of cyanide, which is the main leaching agent for gold recovery. The present study aimed to propose a strategy for metabolic engineering ofB. megateriumto overproduce cyanide, and thus ameliorate the bioleaching process. For this, we employed constraint-based modeling, runningin silicosimulations oniJA1121, the genome-scale metabolic model ofB. megateriumDSM319. Flux balance analysis (FBA) was initially used to identify amino acids to be added to the culture medium. Considering cyanide as the desired product, we used growth-coupled methods, constrained minimal cut sets (cMCSs) and OptKnock to identify gene inactivation targets. To identify gene overexpression targets, flux scanning based on enforced objective flux (FSEOF) was performed. Further analysis was carried out on the identified targets to determine compounds with beneficial regulatory effects. We have proposed a chemical-defined medium for accelerating cyanide production on the basis of microplate assays to evaluate the components with the greatest improving effects. Accordingly, the cultivation ofB. megateriumDSM319 in a chemically-defined medium with 5.56 mM glucose as the carbon source, and supplemented with 413 mu M cysteine, led to the production of considerably increased amounts of cyanide. Bioleaching experiments were successfully performed in this medium to recover gold and copper from telecommunication printed circuit boards. The results of inductively coupled plasma (ICP) analysis confirmed that gold recovery peaked out at around 55% after 4 days, whereas copper recovery continued to increase for several more days, peaking out at around 85%. To further validate the bioleaching results, FESEM, XRD, FTIR, and EDAX mapping analyses were performed. We concluded that the proposed strategy represents a viable route for improving the performance of the bioleaching processes.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据