Extracting Useful Minerals From Industrial Waste With Plants And Fungi

Hemp and sunflowers can clear away radioactive particles and were used for this purpose after the Fukushima disaster. Bacteria can clean mines of residual metals at higher rates than conventional mining. A French company is genetically engineering plants to absorb ever more nickel for use in batteries, alleviating the crunch felt by global scarcity. This field is so promising that this company, Genomines, has received $45 million in investment last month, bringing its total valuation to $92 million.

How can we procure critical minerals and meet the needs of the global economy without atrocious consequences of strip mining? Without being dictated to by China, currently in control of the global minerals supply? How can we clean up existing mine sites and other polluted places without egregious funding?

Odontarrhena chalcidica blooms in Metalplant’s fields in Albania’s Tropojë region. One hectare can produce 200-400 kg of nickel per growing season.

Sahit Muja, Metalplant

Biomining and Bioremediation

Mushrooms and plants can clear up toxic sludges while extracting useful minerals. Biomining (using plants and fungi to extract minerals from soil) can be widely implemented as it’s less destructive than traditional mining and becoming cost competitive. Existing methods are wasteful, whereas biomining is efficient at aggregating dispersed minerals. The techniques can be used with traditional mining to recover what would otherwise be lost. Bioremediation (using living organisms to remediate waste) is cheaper and more efficient than current methods of cleaning up industrial scale pollution. Biomining and bioremediation bridge gaps by presenting novel and low carbon intensity alternatives to conventional mining.

Fungi like to digest and absorb all manner of dead things. Similarly to plants, with all of the variety within the Fungal Kingdom, some fungi will be better adapted for different minerals or contaminants. Merlin Sheldrake demonstrated how oyster mushrooms could be adapted to digest cigarette butts and even grow on his own book. This novelty is amusing, but it exemplifies the important principle of adaptability. Taking advantage of the adaptations that natural selection has yielded these fungi is where future research and tailored mycoremediation programs get interesting.

For mycomining and mycoremediation, several varieties of fungi have already been proven effective. As MIT explains: “Even though the operational costs of bio-mining are a little higher than the cost of traditional mining, more copper can be extracted using bio-mining as the process can be used for more varieties of rock. On average about 60 to 65 percent of the copper from a mine can be extracted using conventional methods whereas 90 to 95 percent can be extracted using bioleaching. Experiments have shown that two fungal strains (Aspergillus niger, Penicillium simplicissimum) were able to mobilize copper and tin by 65 percent, and aluminum, nickel, lead, and zinc by more than 95 percent.”

Some companies that already put these ideas into practice deserve more attention and investment, and Mycomine will offer a tailored program to address their unique needs. This involves analyzing the contaminated site and concluding which types of fungi will be best suited for the specific task. These Swedes are applying methods that are scalable and directly useful, now.

Bioleaching with bacteria deserves attention as it can further fill gaps between the fungi and plants. Certain bacteria, like Acidithiobacillus and Leptospirillum, can clean up abandoned mine sites. They can extract minerals which in turn can be removed from the contamination site. Alternatively, they can fix the minerals and remove the ecological threat by rendering them immobilized.

Some plants collect metals in higher concentrations as a defense mechanism to protect against threats from predators, an adaptation that aggregates metals in these hyperaccumulator plants. We can use this to our advantage by planting them strategically and harvesting these plants, burning the ashes, and from these ashes extracting the desired metal. This technique (phytomining) is far better than strip mining, which is necessarily destructive. While traditional mining can’t be done away with entirely, yet, biomining offers an efficient complement and clean up technique. Even where traditional mining is still to be used, methods like this can address the problems of environmental contamination caused by the conventional mining.

The alternative methods of mining are more expensive and damaging to the environment, as mining critical minerals involves stripping away the entire top layer of earth. Comparing photos of nickel mines in Indonesia with fields of golden flora makes the choice easy.

Biomining in cost competitive with traditional mining and with all of the societal costs considered, it’s clearly advantageous to invest in these adaptable techniques. Mycomining and phytomining don’t have the problems of air and water pollution that traditional mining do, nor do they destroy the landscape like strip mining. The potential is huge as over 700 varieties of hyperaccumulator plants have been identified. They can absorb metals at concentrations of up to 2% of their weight, and researchers are using selective breeding and gene editing to maximize this natural potential. These techniques are emerging and promising and ripe for further research and development.

As a method of cleaning contamination, bioremediation is long established as a superior method. Hemp and sunflowers were planted after Fukushima to absorb cesium-137 and strontium-90. The more that we confront the challenges of our industrialization and the pollution it’s caused, we appreciate that looking to nature will provide elucidation. Logical but brutish methods like digging up rocks are inefficient in the modern age, and elegant solutions are readily available with minor innovations. Advantages to using plants and fungi for this work are that they’re adaptable to different environments and conditions. Some plants like hemp are happy to absorb lots of heavy metals making it useful for clean up; other species are more targeted which is good for focusing on the specifically desired metal for phytomining.

The future for this work seems bright as gene editing bacteria, fungi and plants will open up further opportunities to adjust and maximize an organism’s natural potential, and I’m for one excited to see where this leads. If people want to use CRISPR to bring back the woolly mammoth, which they shouldn’t, surely we can use this technology to make pink pussy tails (Ptilotus exaltatus) even better at recovering phosphorous. Unlike the woolly mammoth project, the phosphorus depletion problem is important. Mining without poisoning our groundwater and atmosphere, clearing away heavy metal contamination from industrial pollution, and undoing the damage of incompetent reactor operators are critically important pursuits as well, and thankfully the fields of biomining and bioremediation will innovatively and synergistically address these problems.