Team:Calgary/Description
INTRODUCTION
To secure a stable and secure supply of rare earth elements for the future without the environment paying the price, recycling will be essential. Our solution utilizes synthetic biology to develop an improved and sustainable method allowing rare earth elements to be recovered from electronic waste and reused in new technologies.
AN OVERVIEW OF REEs
Rare earth elements, also known as REEs, are ubiquitous in modern society, playing major roles in the functioning of automobiles, personal electronic devices, green energy, and industrial technologies [1]. REEs are a group of 17 elements, 15 of which are the lanthanide elements [1]. REEs are relatively abundant in the Earth’s crust, but are found in low concentrations and rarely form large ore deposits [1]. As a result, mining for these elements is difficult, costly, and ultimately unsustainable. China currently accounts for around 90% of the world’s REE supply, the vast majority of which are extracted through ore mining [1]. Demand for REEs has already doubled in the last 15 years, and is expected to skyrocket to 315,000 tonnes by 2030, greatly overshooting current production capacity [2].
As such, the need for an alternative source of REEs is becoming increasingly important, both to diversify the current market and to provide a more sustainable substitute to current processes. REE recycling methods from major sources, such as car batteries, have been a hot topic as of late. Unfortunately, current REE recycling methods involve hydrometallurgy and pyrometallurgy, both of which are detrimental to the environment [2]. Consequently, the need for a sustainable and less-damaging REE recycling process is still a major necessity.
THE E-WASTE ISSUE
Electronic waste, also known as e-waste, is one such non-traditional REE feedstock. Electronic waste includes materials such as computers, batteries, electronics, and appliances. As the fastest-growing solid waste stream, the world produced near 54 million tonnes of e-waste in 2019 [3,4]. According to recent data only 17% of e-waste is properly recycled, and only 1% of REEs from e-waste are recycled, resulting in over $57 billion USD of raw materials wasted annually [4].
Current e-waste recycling processes focus primarily on other valuables found in electronic waste, such as steel, plastics, and precious metals. While this is significant, several other precious materials, such as REEs, fly under the radar. Phenomena such as planned obsolescence and increasing consumerism further contribute to this problem, causing greater amounts of e-waste being sent to landfill [3].
While e-waste recycling processes themselves leave much to be desired, the rules for consumers surrounding e-waste recycling and disposal are also an obstacle [3]. Vague rules and convoluted processes make it difficult for consumers to recycle their electronics - let alone understand the benefits of e-waste recycling. As such, not only do e-waste recycling processes themselves have to improve, but so does increasing awareness surrounding REE and e-waste.
OUR SOLUTION
The recent discovery of lanmodulin, a novel lanthanide-ion binding protein, introduces a biological approach for the recycling of e-waste. Lanmodulin, also referred to as LanM, is native to the bacterium Methylobacterium extorquens, where it is elucidated to play key roles in methanol dehydrogenases [5]. LanM has been found to have a selectivity of 108-fold greater for lanthanides than it has for calcium, and has shown to be non-specific among the elements in the group of lanthanides[5]). Based on this ability, we sought to use LanM protein to separate REE ions from non-REEs in solution so that they can be recovered, recycled, and resold.
Neocycle has chosen to pursue a three-step approach to REE recycling from e-waste. First, our bioleaching subproject uses microorganisms to extract REE ions from e-waste matrices, such as magnets. Second, our metal recovery system immobilizes recombinant LanM fused to a cellulose-binding module onto an adsorber column lined with cellulose beads. Upon the addition of a REE-rich solution from the bioleaching step, the LanM will bind to the REEs. The addition of acid will denature the protein and release the REEs for collection. Interestingly, LanM can be reused in this way several times without drastically losing binding affinity [5]. Finally, the measurement systems were developed to produce a simple protein-based biosensor for REE detection and quantification. They build off of the fact that LanM has no secondary structure when in an unbound conformation, such that the protein can use reporter systems to emit a signal upon folding once it binds to REE ions.
Ultimately, Neocycle hopes to revolutionize the future of e-waste recycling through our three-pronged approach to REE and e-waste recycling. To learn more about Neocycle, keep perusing our wiki!
NEOCYCLE AT A GLANCE
REFERENCES
Ritter S.K. 2017. A whole new world for rare earths. Chemical and Engineering News. 95(34): 30-34.
Pozo-Gonzalo P. 2021. Demand for rare-earth metals is skyrocketing, so we’re creating a safer, cleaner way to recover them from old phones and laptops. The Conversation.
Semeuls A. 2019. The World Has an E-Waste Problem. Time. June 3rd, 2019 issue.
Forti V, Baldé C.P, Kuehr R, Bel G. 2020. The Global E-waste Monitor 2020: Quantities, flows and the circular economy potential. United Nations University (UNU)/United Nations Institute for Training and Research (UNITAR) – co-hosted SCYCLE Programme, International Telecommunication Union (ITU) & International Solid Waste Association (ISWA), Bonn/Geneva/Rotterdam
Cotruvo J.A, Featherston E.R., Mattocks J.A., Ho J.V., Laremore T.N. 2018. Lanmodulin: A Highly Selective Lanthanide-Binding Protein from a Lanthanide-Utilizing Bacterium. J. Am. Chem. Soc. 140(44): 15056-15061.
