Project Introduction
Genetically engineering Acidithiobacillus ferrooxidans for effective biomining
With the rapid development of industrialization and urbanization, the exploitation and utilization of mineral resources have become an important support for human social development. However, in the traditional mining method of pyrometallurgy, a large amount of energy is needed to reach and maintain high temperatures, which requires the burning of large amounts of fossil fuels, resulting in excessively high operating costs; this process also generates harmful gas and greenhouse gas emissions such as SO2 and CO2, which lead to the formation of acid rain and exacerbate global warming problems, even causing climate change, affecting human living environments and the balance of natural ecosystems. At the same time, a large amount of tailings will be produced during the process, which are solid waste generated in the process of mineral processing and extraction, containing unused precious metal elements such as gold, silver, and platinum, as well as toxic heavy metals such as copper, zinc, nickel, chromium, lead, mercury, and arsenic [1]. These metals can penetrate into soil, surface water, and groundwater through geological movement, weathering, and water erosion [2], posing a major threat to ecosystems over a long period of time.
At present, the popular tailings treatment methods are stacking, landfill, solidification. Storage and landfill occupy a lot of land resources, and it is easy to cause natural disasters such as landslide and debris flow. Toxic substances, heavy metals and chemicals in tailings may seep into surrounding water sources, causing water pollution and posing a serious threat to surrounding ecosystems and human health. Tailings ponds typically require large amounts of water to dilute and transport waste, which can cause surface and groundwater levels to drop. It has a serious impact on nearby farmland, wetlands and groundwater resources, destroying the ecological balance and biodiversity. Although the curing treatment can reduce the harm of the tailings, it needs to add a lot of lime, cement, etc., which is high in processing cost and difficult to recycle. And the curing process is complex, requiring high input equipment, human resources and other resource costs. Based on current treatment methods, tailings treatment technology is not mature, and the potential utilization value of tailings has not been fully explored. Tailings treatment has become a major problem in economic, social and environmental development[3].
Tailings area
Worker: Classmates, there are tailings wastewater generated during the mining process. If directly discharged, it will cause environmental pollution.
Kid: It will also have an impact on human health!
Worker: So how to effectively deal with them is an important issue for protecting the environment.
Tailings area
Acidithiobacillus ferrooxidans: I can contribute to the treatment of wastewater!
Child: How to handle it!
Acidithiobacillus ferrooxidans : We can withstand strong acid, but we need the help of scientists to further treat wastewater and even turn waste into treasure.
Laboratory scene
Scientist: That's right, we can genetically engineering Acinethiobacillus ferroxidans to promote the binding to minerals, allowing heavy metals to leach in tailings wastewater.
Acidithiobacillus ferrooxidans: That's right, not only that, we can also achieve specific gold leaching, but this also requires the insertion of specific gold detection module.
Laboratory scene
Scientist: Oh, by the way, treated wastewater cannot be directly released, otherwise it will have an impact on environmental safety.
Acidithiobacillus ferrooxidans: I have a killing switch in my genome that will commit suicide when released into nature to meet safety needs.
Given the global increase in demand for mineral resources and the decline in ore grades, there is an increasing utilization of microorganisms in biomining to extract valuable metals from low-grade ores and electronic waste. Biomining offers a sustainable and environmentally friendly alternative to conventional mineral processing technologies. However, it faces challenges such as long leaching cycles, low extraction efficiency, and unspecific bioleaching. The genetic engineering of microorganisms through synthetic biology presents a promising approach to enhance their capabilities for improved biomining performance. Acidithiobacillus ferrooxidans, a genus of extremophilic acidophiles commonly inhabiting mining process waters and acid mine drainage, is a promising chassis for metal recovery and bioremediation of metal-contaminated sites. In 2024, CUG-China aims to enhance biomining efficiency for nonferrous metals, such as gold and copper, by genetically engineering Acidithiobacillus ferrooxidans. This engineered strain incorporates three key genetic modules, including a cyclic di-GMP synthesis module for the enhancement of bacteria-ore interactions, a gold-specific detection module for targeted recovery, and an electron transfer module for further improving biomining processes.