circular-economy – Chasing Tales

E-Waste – III: Biomining

This is the third in a series on e-waste. Post I established the scale of the problem and the concept of urban mining. Post II examined India’s informal recycling sector and the limits of EPR policy. This post looks at the biotechnology frontier.

Rare Earth Elements, or REES, are not, despite their name, particularly rare in the Earth’s crust.¹ The challenge is that they are seldom found in concentrated deposits², and they almost always occur together, sharing such similar chemical properties that separating one from another is technically demanding and chemically intensive.³ That cost is not merely financial. Conventional REE mining generates radioactive waste, strips landscapes, and produces acid drainage that contaminates groundwater for decades.⁴

Also, China currently supplies nearly 90% of the world’s REE demand⁵, a concentration of geopolitical risk that rattled supply chains as recently as 2019⁶, and the geopolitical situation has escalated dramatically since: on April 4, 2025, China introduced export restrictions on seven rare earth elements in direct retaliation for U.S. tariffs⁷ ⁸. In October 2025, China expanded those controls further, adding five more REEs critical to magnets and defense, including erbium.⁹ China did pause some of these restrictions temporarily in late 2025 following U.S.-China trade negotiations, but analysts universally treat the pause as tactical, not structural.¹⁰¹¹ The leverage remains.

E-waste has become one of the fastest-growing solid waste streams in the world, with approximately 62 million tonnes generated globally in 2022 alone¹², of which less than one quarter was documented as recycled¹³, yet global REE recycling rates remain below 5%¹⁴. Meanwhile, global demand for magnetic REEs alone is projected to surge from 59 kilotonnes in 2022 to 176 kilotonnes by 2035, a tripling in just over a decade. The trajectory is not sustainable.¹⁵

What are REEs?
Here are the 17 elements, actively sounding like Tolkienian characters:¹⁶

The 17 Elements: Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Promethium (Pm, the only actually rare REE, and named for Prometheus), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (Lu), Scandium (Sc), and Yttrium (Y).
Light vs. Heavy REEs: They are classified into Light Rare Earth Elements (LREEs) (atomic numbers 57-63) and Heavy Rare Earth Elements (HREEs) (atomic numbers 64-71), with yttrium grouped with heavies. HREEs are generally rarer and more valuable. HREEs are more valuable: their greater scarcity relative to demand, and the fact that dysprosium and terbium (both the HREEs) are the critical additives that keep NdFeB magnets performing at high temperatures in EV motors, making them essentially irreplaceable in the short term.¹⁷

Currently, global REE recycling rates remain below 5%. Yet the secondary sources are remarkably rich. The permanent magnets in hard disk drives contain neodymium, dysprosium, and praseodymium at concentrations of 2,500–15,000 parts per million, while the phosphors in fluorescent lamps carry yttrium, europium, cerium, terbium, and lanthanum at 1,000–20,000 ppm, concentrations up to 17 times higher than in natural ores.¹⁸ ¹⁹

Biomining
Using biological organisms to aid mining.

The biological mechanisms involved span a sophisticated toolkit:²⁰

Bioleaching: Microorganisms produce organic acids, siderophores, or other metabolites that dissolve metals from solid matrices. The bacterium Gluconobacter oxydans, for instance, produces gluconic and pyruvic acids that leach REEs from nickel-metal hydride battery powder.
Biosorption: Metal ions bind to functional groups on microbial cell walls or to engineered biomolecules, concentrating them from dilute solutions.
Bioprecipitation: Microbes convert dissolved metals into insoluble forms that can be physically separated.
Bioaccumulation: Some microorganisms, particularly microalgae, internalize REEs through metabolic processes, serving as biological concentrators.
Bioweathering and Bioflotation: Additional mechanisms studied for low-grade ores and mine tailings.

What differentiates biological from chemical approaches is the operating philosophy. Conventional hydrometallurgy uses strong inorganic acids (sulfuric, hydrochloric, nitric) at high temperatures, generating large volumes of hazardous waste. Biomining operates largely at ambient conditions, using biodegradable lixiviants (liquid chemical solutions used in hydrometallurgy to selectively extract metals from ore or recycled materials by dissolving them into a liquid phase)²¹, with significantly reduced freshwater consumption and wastewater generation.

Urban Biomining
It is the recovering of critical resources from the waste streams of cities and industrial systems rather than from natural ores.²² ²³ A 2025 review published in ACS Environmental Au by researchers at George Washington University identifies it as one of the most promising frontiers in sustainable REE recovery.²⁴

Laboratory studies have demonstrated impressive bioleaching yields. Acetic acid achieves leaching efficiencies exceeding 90% for neodymium, dysprosium, and praseodymium from NdFeB magnet powder at concentrations of 1.6–10 mol/L and 60°C.²⁵ ²⁶ Citric acid at 1 mol/L can achieve near-complete (100%) REE leaching from hydrogen-decrepitated (a process used to create extremely small grains)²⁷ NdFeB powder within 24 hours.²⁸ Importantly, the spent culture medium of microorganisms (or supernatant, which is the byproduct liquid remaining after microorganisms have grown, containing metabolic waste, secreted proteins, and residual nutrients)²⁹ often outperforms isolated organic acids, because it contains a richer diversity of leaching agents at higher combined concentration.³⁰ ³¹

A two-step bioleaching process using acidophilic bacteria on e-waste shredded dust was found to mobilise up to 99% of cerium, europium, and neodymium, and up to 80% of yttrium and lanthanum within eight days.³² A sequential microbial process pairing bacterial bioleaching with microalgal biosorption has demonstrated the feasibility of recovering multiple REEs (gadolinium, praseodymium, cerium, lanthanum) from e-scraps.³³

Beyond e-waste, biomining offers a pathway into legacy waste. Coal ash, the residue from burning coal, is one of the most REE-rich and economically promising secondary sources.³⁴ A techno-economic analysis cited in a 2024 comprehensive review found that coal ash yields the highest profitability of all mining waste streams when subjected to biomining recovery.³⁵ Old mine tailings, the rock and mineral residues left behind after primary extraction, also retain significant REE concentrations.³⁶ ³⁷ Biomining these sites simultaneously addresses long-term environmental hazards, reducing acid drainage and radioactive residue exposure, while turning environmental liabilities into resource streams.³⁸ ³⁹

Selectivity
Since rare earth elements are chemically near-identical, so finding just one among the 17 is a complex process, and can require hundreds of solvent extraction stages via conventional methods.⁴⁰

This is where molecular biology can help.

In 2018, researchers discovered lanmodulin (LanM)₄₁, a small (~12 kDa- according to Google AI, a teaspoon holds over 200 quintillion particles)⁴² bacterial protein produced by methylotrophic bacteria that is able to select the required REE to a degree no synthetic chemical method can yet do.⁴³ It also remains stable at pH 2.5 and temperatures up to 95°C, making it practically viable in the acidic, hot conditions of industrial leachates (industrial leachates are the highly contaminated, toxic liquids formed when water percolates through industrial waste, landfills, or contaminated sites, dissolving soluble materials)⁴⁴.⁴³

Beyond lanmodulin, the field has expanded to include:

Lanthanide-binding peptides (LBPs)⁴⁵: Short synthetic sequences that selectively adsorb specific REEs with minimal cross-reactivity for neighboring non-REE elements
Functional nucleic acid aptamers⁴⁶: A DNA aptamer (Sc-1) has demonstrated the ability to bind REE ions selectively and discriminate all 17 REEs into three groups.
Pyrroloquinoline quinone (PQQ)⁴⁷: A microbial cofactor that can precipitate REEs from solution and has a natural preference for light REEs over heavy ones
Lanthanide-binding phage (LBPh)⁴⁸: M13 bacteriophage engineered with ~3,300 copies of an LanM-derived peptide, achieving 35 mg/g binding capacity with preferential uptake of heavy REEs and pH-triggered release over five reuse cycles

Don’t look at me, I cannot pronounce these words either. I was researching urban mining and fell into this ~~black~~ rabbit hole.

What biomining-enabled circular REE recovery ultimately points toward is not merely a more efficient way to recycle old phones. It is a fundamentally different relationship between industrial civilisation and the material world, one in which the waste of one cycle becomes the feedstock of the next, in which biology does the discriminating work that chemistry does badly and expensively, and in which the geopolitical concentration of a critical resource is loosened by distributing recovery capacity to wherever waste accumulates.

This vision aligns with what some materials scientists and industrial ecologists call a regenerative materials system⁴⁹: one that does not merely reduce harm but actively restores, cleaning up legacy pollution in mine tailings and coal ash while simultaneously supplying the materials a decarbonizing economy urgently needs. The circular economy of REEs through biomining represents exactly this kind of convergence: biotechnology, sustainability science, and critical materials security not pulling in different directions, but pointing the same way.

The technology is not yet ready for full industrial deployment. But the science has reached the point where the question is no longer whether it is possible, but how fast we choose to make it happen.

Sources

The economics of remanufacturing

Remanufacturing is a structured industrial process where a used product (the “core”) is disassembled, cleaned, inspected, repaired or upgraded, and reassembled to at least “as‑new” performance, often with a new warranty. It differs from simple repair (which restores function) and recycling (which recovers materials) by preserving the value embedded in complex components like housings, castings, and precision parts.¹

In circular economy terms, remanufacturing is one of the highest‑value loops because it keeps products in use with minimal additional material and energy input. That makes it strategically attractive in sectors where products are capital intensive, long‑lived, and technically durable—think engines, industrial equipment, medical devices, and high‑end electronics.²

Remanufacturing reduces exposure to volatile raw material prices and supply disruptions, a growing concern highlighted in circular economy policy discussions by conserving the bulk of materials in complex products³ and reports indicate that remanufacturing can cut greenhouse gas emissions by two-thirds or more compared with producing new parts, making it economically attractive for firms facing carbon constraints or reporting obligations.⁴ This is why policies that push producers to take responsibility for products at end‑of‑life (through take‑back schemes or design requirements) naturally encourage remanufacturing models as they can extract more value from returned goods.⁴ ⁵

Economics
The economics is all about the margins for organisations:

Cost side

Production cost savings: Many empirical and industry studies show remanufacturing can reduce unit production costs by roughly 40–65% compared with making a new product, mainly by reusing major components and cutting material and energy demand. Industry examples like Caterpillar’s “Cat Reman” report remanufactured parts costing 45–85% less to produce than brand‑new equivalents while meeting the same specifications.⁶
Customer price level: Remanufactured products are typically sold at 60–80% of the price of new products, attractive enough to win price‑sensitive customers while still leaving room for solid margins.⁷
Resource and energy savings: Preserving existing components means far less raw material and process energy; some studies and industrial programs report 65–87% cuts in energy use and greenhouse gas emissions relative to new manufacture.⁸

Cost Structures

Predictable core supply, stable technical yield, and cost‑efficient operations are the most important factors in any business working in the remanufacturing sector. These can be divided into three main factors, which are then further subdivided as shown in the list below:

Core acquisition and collection: Remanufacturers must get used products back, through buy‑back programs, deposits, leasing, or authorised channels (approved distribution or collection pathways), which adds logistics, handling, and sometimes incentives to the cost base.⁹ Economic models and case studies show that profitability is highly sensitive to the “core return rate”: low or erratic returns undermine capacity utilisation and can drive up unit costs.¹⁰ Interestingly, research on “seeding” (deliberately placing additional new units into the field to increase future cores) finds that active management of core flows can increase total remanufacturing profits by around 20–40%¹⁰ in some product lines: this means the business depends on both- active new sales, and a specific life of the products which are being sold.
- From an economic perspective, the supply of cores is not an exogenous input but an intertemporal decision variable. New products placed into the market today become the core inventory available for remanufacturing in the future, linking current sales decisions to future production capacity. Formal models show that firms may rationally increase new product sales, adjust leasing terms, or subsidise returns in order to secure a predictable flow of future cores, even when short-term margins are lower. The profitability of remanufacturing therefore depends on managing a stock of recoverable products over time rather than on one-period cost comparisons. When core returns are volatile or poorly controlled, remanufacturing capacity cannot be fully utilised. Unit costs rise and the apparent economic advantage shrinks, even if average cost savings look attractive on paper.
Core quality and yield: Not all returned products are economically remanufacturable; if too many cores fail inspection or require heavy rework, the effective cost advantage shrinks.¹⁰ Models that combine technical constraints with cost and collection rates show that limited component durability and uncertain core quality can make remanufacturing unprofitable unless screened and priced correctly.¹¹
- A further economic complication is uncertainty. Unlike new manufacturing, where inputs are standardized, remanufacturing faces stochastic variation in both core quality and remanufacturing cost. Inspection and testing therefore act as economic screening investments rather than mere technical steps: firms incur upfront costs to reveal information about whether a core should be remanufactured, downgraded, or scrapped. Economic models frame this as an option-value problem, where remanufacturing decisions are deferred until uncertainty is resolved. Even when average remanufacturing costs are low, high variance in core condition can reduce expected profits and lead firms to reject a substantial share of returns. This helps explain why observed remanufacturing volumes are often lower than simple cost‑savings calculations would predict.
Process Complexity: Disassembly, inspection, testing, and reassembly require specialised skills and flexible processes, which can raise overhead relative to straight‑through new manufacturing.¹²
Overheads: Since remanufacturing has extra process steps (process complexity), overhead is often a larger share of total cost than in straightforward new manufacturing.¹³

Revenue side

Margin structure: If a new product sells for 100 monetary units and costs 70 to make, the margin is 30; a remanufactured equivalent might sell for 70–80 and cost only 30–40, producing a margin in the same range or better.⁶
New customer segments: Lower price points allow firms to address more price‑sensitive markets, geographies with lower purchasing power, or customers who would otherwise buy used or off‑brand products.⁹

A central economic tension in remanufacturing is cannibalisation: every remanufactured unit sold potentially displaces a sale of a new product. Economic models consistently show, however, that remanufacturing can increase total firm profit when it functions as a form of price discrimination rather than simple substitution. By offering a lower-priced remanufactured product, firms can capture demand from customers with lower willingness to pay who would otherwise buy used, grey-market, or competitor products, while preserving higher margins on new products for less price-sensitive customers. In this equilibrium, remanufactured products expand the market rather than erode it, provided the price gap between new and remanufactured goods is carefully managed. This logic explains why OEMs often restrict remanufacturing volumes or channels even when unit margins are attractive: the optimal remanufacturing rate is determined not by production cost alone, but by its interaction with new-product pricing and demand segmentation.

Market Structures
At the moment, remanufacturing markets tend to be fragmented and dominated by many small third‑party firms, with pockets of oligopoly or even monopoly power (A monopoly is a market structure where one firm dominates the entire market supply, and an Oligopoly is a market structure with only a few suppliers in the market rather than many) around strong brands and OEM‑controlled (OEM = Original Equipment Manufacturer) take‑back systems. The exact structure depends on who remanufactures (OEM vs independent), how products are collected, and how new and remanufactured products compete in closed‑loop supply chains.¹⁴ ¹⁵

From an industrial-economics standpoint, the persistence of fragmented remanufacturing markets reflects the shape of remanufacturing cost curves. While new manufacturing often exhibits strong economies of scale, remanufacturing benefits from scale only up to a point. Input heterogeneity, variable inspection effort, and the need for flexible processes limit the gains from large-scale standardisation. As volume increases, coordination and screening costs rise, flattening the cost curve and reducing the competitive advantage of very large firms. These structural features help explain why remanufacturing markets tend to support many small and mid-sized firms alongside selective OEM participation, rather than converging toward high concentration.

In remanufacturing, market structure is usually discussed along three dimensions:¹⁶

Industry concentration: how many firms remanufacture a given product, and how large the biggest players are.
Vertical structure in the closed‑loop supply chain: which tiers (OEM, retailer, specialist remanufacturer, collector) perform remanufacturing and who controls access to cores (used products).
Horizontal competition: how new and remanufactured products compete (prices, perceived quality, channels), often modeled with monopoly, duopoly or oligopoly game‑theoretic frameworks.

These structures are shaped by cost savings from remanufacturing, consumer valuation of remanufactured products, regulatory pressure, and how easy it is to access used products (cores).

Empirical industry structures¹⁶
Across sectors such as automotive parts, industrial machinery, electronics and heavy equipment, studies and market reports converge on a broadly fragmented structure with a long tail of small non‑OEM remanufacturers and a smaller number of large OEMs and global service providers.

Key empirical patterns:

Automotive parts: global automotive parts remanufacturing is characterised as fragmented, with many regional and local remanufacturers, plus major OEM programs (e.g., engines, gearboxes, turbochargers).¹⁷
Industrial machinery and heavy equipment: growth is strong, but the market still has many specialised firms; OEMs, dealer networks and third‑party remanufacturers often coexist, sometimes in parallel closed‑loop chains.¹⁸
Overall EU/US picture: an EU‑level study notes a skewed structure with “a significant number of smaller non‑OEMs” and relatively few large OEM‑affiliated remanufacturers.

This leads to typical hybrid structures:

Many small firms competing in price and service quality for commodified parts.
Local monopolies around niche technologies or proprietary know‑how.
Regional oligopolies in popular product lines (e.g. certain automotive components).

What’s happening in India?
India’s remanufacturing story is still nascent and uneven, but it is being pushed forward indirectly by waste‑management laws, Extended Producer Responsibility (EPR) rules for e‑waste, plastics and batteries, and the historic strength of the kabadiwala / scrap‑dealer ecosystem. Most circular‑economy action on the ground still looks like repair, reuse and informal recycling rather than full OEM‑style remanufacturing, yet the latest e‑waste rules and their refurbishing‑certificate mechanism create legal hooks that remanufacturing‑type businesses can use.¹⁹ India doesn’t yet have a “Remanufacturing Act”, but multiple waste rules create incentives and legal categories that overlap with remanufacturing.

E‑waste (Management) Rules²⁰

The 2022 Rules:

Put legal responsibility on producers, manufacturers, refurbishers and recyclers of listed electrical and electronic equipment to meet quantified EPR targets for e‑waste, using a central online portal.
Require all these actors (including refurbishers) to register on the CPCB EPR portal, report flows of products and e‑waste, and obtain authorisations before operating.
Explicitly recognise refurbishing as a distinct activity: registered refurbishers can extend the life of products, send any residual e‑waste only to registered recyclers, and generate refurbishing certificates that allow producers to defer part of their EPR obligation into later years.

The 2024 Amendment Rules keep the 2022 structure but tune how the system actually works:

They add a new rule 9A that lets the central government relax timelines for filing returns “in public interest or for effective implementation”, acknowledging practical compliance bottlenecks.
They refine definitions (including “dismantler”) and insert new sub‑rules in rule 15 that allow the government to create platforms for exchange/transfer of EPR certificates and empower CPCB to set floor and ceiling prices for those certificates, tying prices to environmental‑compensation logic.

That last bit is important: it means refurbishing and recycling certificates now sit inside a semi‑regulated compliance market, rather than in a completely opaque bilateral space. For any firm doing serious refurbishment or remanufacturing of electronics, the financial value of each “saved” device is no longer just the resale price; it also includes the value of refurbishing certificates producers will need to meet their EPR targets.

One of my favourite things about waste management in India is the local kabadiwala (waste-person) system, where a person who runs a reverse-logistics business comes to people’s homes and BUYS the waste they wish to remove from their homes. The kabadiwala networks that move e‑waste and scrap in cities haven’t changed because of the 2024 amendment—but the way the state talks about integrating them has become more concrete.

Official statements on the 2022 rules repeatedly say the new EPR regime is meant to “channelize the informal sector to the formal sector”, by making collection and processing possible only via registered producers, refurbishers and recyclers.²¹ Circular‑economy concept notes for municipal waste still highlight that informal workers and kabadiwalas do the heavy lifting of collection and separation, and must be integrated into contracts, data systems and formal infrastructure.²² Case studies on informal e‑waste collectors (kabadiwalas) emphasise that they remain the primary collection channel for household e‑waste, but usually sell to small dismantlers who operate outside the 2022–2024 EPR framework.²³

Against that backdrop, the 2022–2024 e‑waste regime offers two big levers for integration:

Partnerships between registered refurbishers/recyclers and kabadiwala networks: the law doesn’t mention kabadiwalas by name, but nothing stops a registered refurbisher from building sourcing and sharing arrangements with informal collectors, bringing their material into the formal portal system.²⁴
Data and platform logic: the new certificate‑trading platforms and CPCB portals are building a data spine for reverse logistics; if cities and social enterprises plug informal actors into that spine, kabadiwalas become the front‑end of a traceable, compliance‑generating remanufacturing pipeline instead of sitting outside it.²⁵

In practice, though, most of what happens today is still repair, cannibalisation for parts, and low‑value recycling. The regulatory architecture is now sophisticated enough to support high‑value remanufacturing and refurbishment at scale, but the hard work is social and institutional: defining quality standards, building trust in “remanufactured” products, and finding ways to bring kabadiwalas and other informal workers into those new value chains without erasing their livelihoods.

Sources

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