In February 2022, the Canadian government’s Digital Technology Supercluster mounted a C$16 million hunt for rock-eating microbes. Over the next two years, its newly launched Mining Microbiome Analysis Platform (MMAP) will collect genetic data on microorganisms that use mineral ores as nutrient sources, releasing economically valuable elements in the process. In its search for suitable strains, the project will scour 15, 000 mining sites – extreme, mineral-rich ecosystems likely to harbour species that specialise in metabolising rock.
Led by Vancouver-based natural resources company Teck Resources, MMAP will foster collaborations between mining companies and genomics sequencing company Illumina. The bioresources inventoried by the project may one day be adopted by the mining industry as safer, greener alternatives to conventional extractive chemicals.
The problems with high-tech metals
Canada’s bio-prospecting programme aims to shore up the sustainability and supply chain security in critical metals, a class of high elements that support colour displays, rechargeable batteries, camera lenses, and audio amplification in electronic devices. Their unique properties enable gadgets to function at speed even as they become lighter and smaller. Although global production in critical metals doubled between 2005 to 2015, demand from the tech industry is rising and the materials do not come cheaply. Gallium, found in phone semiconductors, currently costs around $872.40 per kg.
One subset of critical metals is especially sought after by industry. These are the rare earth metals, seventeen elements that are vital for building electric cars and other renewable devices. Each comes with mystical-sounding names and hefty price tags. Neodymium now goes for $230.60 per kg while praseodymium is at $241.80. Terbium, used in low-energy light bulbs, sold for around $2,401 per kilo in March 2022. The other rare earths are scandium, lanthanum, cerium, praseodymium, promethium, samarium, europium, gadolinium, holmium, erbium, thulium, ytterbium, and lutetium.
Despite their value, less than 1 percent of critical metals are recovered from spent electronic products each year. This wastage is concerning given that the global metals mining industry is notorious for its damaging social and environmental impacts. Under conventional chemical extraction methods, concentrated sulfuric acid is used to dissolve ore. The techniques generate toxic and even radioactive waste streams that contain thorium and uranium from mined rock as well as hydrogen fluoride and acidic water. As a result, many former extraction sites are littered with abandoned settlements and toxic waterways. On top of their eco-toxicity, these processes are highly inefficient for extracting metals present at low concentrations.
On top of these social and environmental concerns are fears around global supply shortfalls. This has less to do with the natural scarcity of these elements than the geopolitically fraught nature of their supply chains. Despite the name, rare earth metals are relatively abundant in the earth’s crust. Cerium is the 25th most common element– just below nickel, zinc, and copper – while neodymium comes in at 27th and yttrium at 29th. The problem is that only a few countries hold accessible reserves, meaning prices and flow volumes are dependent on the quality of trade relations between importer and exporter nations. China, which supplies 85 percent of the global product, holds an estimated 44, 000, 000 tonnes of rare earth minerals within its borders. The next biggest reserves are in Vietnam and Brazil, both at 22, 000, 000 tonnes, followed by Russia with 12, 000, 000 tonnes. The US only holds 1,500, 000 tonnes while Europe’s pool is limited to Greenland (1,500,000). The EU relies on imports for 100 percent of its neodymium, dysprosium, and praseodymium.
Policymakers fear future tensions between the US and economically developing states may threaten the flow of critical metals to the West. In 2010, a diplomatic incident between the US and China over the latter’s rare earth export caps led to soaring global metals prices. Many now believe that biomining offers a way of reducing environmental impacts in mining while ensuring a reliable supply for nations with low natural reserves.
Microbial mining is not completely new. Since the 1950s, microorganisms have been used to extract sulphide metals, covering copper, cobalt, platinum metals, gold, silver, zinc, and iron. Around 10-20 percent of global copper is mined with microbial biotech. However, biobased mining techniques for other critical metals are less developed and will require different microbial species. Identifying strains that will work on different ores and metals is the driving purpose behind Canada’s genetic databasing project.
Microbes extract metals in one of two ways. In one approach, microbes eat away at the ore that encases the target elements. In another technique, microbes turn target metals inside the ore into a liquid soluble form while leaving the ore intact. This makes it easier for other chemicals to then extract the dissolved metals from the mineral matrix.
There are already well-established companies operating in the biomining space. Bactech Environmental Corporation, founded in 1994, is perhaps the most significant. This Canadian environmental technology company offers gold, silver, cobalt, and copper microbial mining solutions at a commercial scale. Within days, bacteria inside their bioreactors will oxidise sulphide mineral ores to reveal gold and other metals. Since the late nineties, the company has built microbial mining facilities for clients around the world, including in South Africa and Mexico. In 2001, it commissioned China’s first commercially proven bioleaching plant in Shandong Province, China.
In a major new construction project, Bactech Environmental will build a new bioleaching facility for Ecuadorian gold mining client Ponce Enriquez. Microbial mixes will be used to process gold from three types of arsenopyrite and pyrite ores. The company tested the technical and environmental viability of their techniques with partial funding from the Ontario government.
Although Canada is a particularly active hotspot for biomining R&D, other states are also investing. The tech’s potential geopolitical dividends have not been lost on the Pentagon, which in 2021 launched a DARPA biomining research project into biobased mining for military technology. The programme, which goes by the name of ‘Environmental Microbes as a BioEngineering Resources’, will investigate ways of scaling bio-based separation and purification. The French Geological Survey has its own programme aimed at gaining autonomy from foreign supply chains.
While biobased extraction can reduce the environmental impacts of mining, there are even more sustainability gains to be made from bio-based recovery of metals in e-waste. In 2019, the world lost an estimated $57 billion worth of high-value commodities to disposed electronics. With this waste stream growing at a rate of 3-5 percent annually, elemental reserves in disposed products now rival the value and volume of those found in natural reserves.
Germany’s industrial biotech company BRAIN AG is an established name in the critical metals recycling niche. It entered the green mining sector in 2009 and has since compiled a bio-archive consisting of tens of thousands of microbes. This is BRAIN AG’s pool of ‘functional biomass’ from which it draws custom biotech solutions. One of its products is a microbial biosolvent that recycles lithium and cobalt from used EV batteries. It uses bioleaching, where microorganisms dissolve the target metals and leave the surrounding materials solid. Inside their bioreactors, the microbes feed on organic waste streams such as beet syrup, crude glycerol from biodiesel production, or pomace from vegetable or fruit processing.
NS2, an IT lifecycle management company in England, is the first UK company to extract critical metals using bioleaching. After a 6-month trial conducted with Coventry University in 2021, they developed a method for removing gold and copper from printed circuit boards. After doubling turnover in 2021, N2S decided to grow their bioleaching venture under a new and dedicated sister company named Bioscope Technologies.
Critical metals for renewable tech
Although biomining products for gold, copper, lithium, cobalt, and nickel are now on the market, the more exotic metals needed in solar panels, EVs, and wind turbines are still in need of cost-effective solutions. Extraction and recovery remain at the laboratory stage for materials like neodymium, dysprosium, and praseodymium.
The absence of biobased solutions for high tech critical metals presents today’s renewable tech industry with a sustainability dilemma. Each of the estimated 10.1 million electric vehicles that will be built in 2026 will contain around a kilogram of critical elements in their batteries alone. Demand for neodymium, used in almost all EV and wind turbine magnets, will likely explode in the coming decade. Without green and circular sourcing strategies for metals, decarbonisation is headed on a collision course with other important environmental targets such as biodiversity, air quality, and soil quality.
The EU is trying to fix this by investing heavily in microbial recovery R&D. Its BIORECOVER programme draws together fourteen partners from the mining, microbiology, chemistry, engineering, metallurgy, sustainable process development, and end-user sectors. Its objective is to develop efficient recovery processes for diverse metals, including yttrium, manganese, palladium, iridium, and platinum. By late 2021, it had identified promising candidate microbes and had already conducted extractive experiments. Eventually, the group will assess the most high-performance techniques by offering prototypes to commercial end-users for testing.
The recent surge in biomining research is partly in anticipation of demand growth from the renewable tech industries but also rests on general advances within biotech. The genomic tools required for selecting, customising, and culturing strains have only emerged over the last two decades. Because it promises greater resource independence for importing nations, bio-recovery is enjoying perhaps the most intensive collaborations between governments, universities, and the private sector of all biotech fields today. These efforts bode well for the beginnings of circularity in high-tech manufacturing, a problem that will only become more pressing as the energy transition gains pace.