From waste to worth: Circular bioeconomy opportunities in the global potato chain

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By Lukie Pieterse, Potato News Today

This feature explores how potato processors and growers can turn peel, wastewater and culls into energy, ingredients, bio-based materials and fertilizer – and asks who will capture the value in a circular potato economy that is fast moving from theory to practice.

Potato processors and packers have long treated waste as an inevitable cost of doing business – something to haul away, spread on land, or send to the nearest lagoon. That attitude is shifting.

As food loss and waste move up the policy agenda, and as energy, fertilizer, and compliance costs climb, the by-products of the potato chain are being re-imagined as feedstock for a circular bioeconomy: ingredients, energy, platform chemicals, bio-based materials and environmental services.

The question is no longer whether potatoes can fit into a circular model, but who will capture the value, on what terms, and how fairly that value will be shared along the chain.

How big is the potato waste stream – and why it matters

Globally, food loss and waste remain stubbornly high. UN agencies estimate that roughly one third of food produced for human consumption is lost or wasted along the chain, with roots and tubers among the commodity groups with the highest loss rates.

Within that, potatoes stand out:

  • A large share of global potato production is processed in some form – fries, chips, flakes, starch, dehydrated products or animal feed.
  • A typical potato processing plant can generate several percent of incoming raw material as peel and trimming waste, plus additional off-spec product and high-strength wastewater.
  • In high-income regions, additional losses accumulate at field level through mechanical damage, grading standards and contract specifications; in low- and middle-income regions, on-farm and storage losses dominate.

Historically, much of this material has gone to low-value uses such as bulk animal feed, or has simply been treated as a disposal problem. Recent scientific reviews of potato waste valorization make it clear, however, that these streams contain significant energy and biochemical value, and can support multiple high-value product lines if handled as part of an integrated biorefinery concept.

In other words, the “waste” footprint of the potato sector is also its largest underused resource.

Mapping the potato waste and by-product streams

The main side-streams along the potato chain can be grouped as follows:

  • Field and storage losses: undersized, misshapen or damaged tubers, culls from disease or sprouting, and downgrades due to cosmetic standards or contract specs.
  • Packing and fresh-cut waste: peel, trimmings, rejected tubers, wash water solids from grading and washing.
  • Processing by-products:
    • Peel and small trimmings from peeling, cutting and forming
    • Cook water and “potato juice” from cutting, blanching and pre-frying
    • Pulp and starch cake from starch extraction and dewatering
    • Off-spec fries, chips and hash brown products
    • High-COD (chemical oxygen demand) process wastewater from multiple steps
  • End-of-life losses: retail and household food waste – less attractive for high-end valorization due to mixed contamination, but still relevant for energy recovery in some systems.

Each of these side-streams has a different composition and is suited to different circular pathways – from relatively simple uses such as cattle feed to more sophisticated routes like bioplastic production, lactic acid fermentation or tailored biochar.

For growers and processors, the first practical step is simply mapping volumes and qualities with some accuracy. Without that, everything else is guesswork.

Food and feed ingredients: turning peel into nutrition and functionality

Potato peel is often treated as a nuisance, yet its composition tells a different story. Studies consistently show that peel streams contain:

  • Higher levels of dietary fibre than the peeled tuber
  • Concentrated phenolic compounds and antioxidants
  • Useful levels of protein, minerals and residual starch

This has triggered a wave of work on peel-derived ingredients:

  • Dietary fibre concentrates: dried and milled peel can be refined into fibre ingredients that improve texture and water-holding in baked goods, meat analogues and gluten-free formulations. For food companies under pressure to increase fibre content while keeping labels short, potato peel is an attractive raw material.
  • Natural antioxidant extracts: phenolic-rich extracts from peel are being tested as clean-label preservatives to delay lipid oxidation in fats and oils, and as active components in edible films and coatings. These could partially displace synthetic antioxidants and help processors meet “clean label” targets.
  • Functional powders: blends of peel and pulp can produce functional flours for bakery or snacks, replacing a portion of wheat or maize flour while adding fibre and micronutrients. For potato processors already handling large volumes of raw material, the incremental cost of producing such powders can be competitive.

At the same time, whole potatoes, culls and mixed processing waste remain valuable as animal feed. Potato waste meal (produced from whole rejects, pulp and peelings) typically has high energy value and modest protein content, making it a suitable energy source in rations for feedlot cattle and other livestock when properly balanced with protein sources and minerals.

The challenge for processors is that food and feed ingredients require consistent quality and hygienic handling – which can mean investment in dedicated separation, drying and milling lines. Where volumes justify it, this can shift peel from a disposal cost to a modest profit centre, or at least to a cost-neutral, risk-reducing stream.

Biogas and energy: wastewater as a fuel, not a liability

Few by-products are as overlooked as potato processing wastewater and “potato juice” from cutting, blanching and starch extraction. Rich in starch, soluble sugars and proteins, these streams carry a very high organic load and therefore high treatment costs – but they are also excellent substrates for anaerobic digestion.

Commercial experience and research point in the same direction:

  • Potato juice and other starchy side-streams can be converted efficiently into biogas, with methane yields boosted by their readily degradable carbohydrates and proteins.
  • Large potato processors increasingly combine high-rate anaerobic digesters with post-treatment steps, digesting the bulk of the organic pollution load and generating biogas for steam or electricity on site.
  • The resulting digestate, once dewatered, can serve as a soil conditioner and partial fertilizer substitute, closing nutrient loops back to agriculture.

For many companies, this is the most mature circular route:

  • It solves an environmental compliance problem (wastewater treatment).
  • It reduces purchased energy costs.
  • It can improve the processor’s carbon footprint in a way that is straightforward to document for customers and regulators.

The main barriers are capital cost, technical know-how and, in some locations, a lack of policy support for on-site renewable energy compared with grid electricity. Smaller processors may struggle to justify standalone digesters, but can sometimes join regional biogas hubs or share infrastructure with municipal plants or other food factories.

From starch waste to platform chemicals and organic acids

Beyond biogas, potato side-streams can be “upgraded” via fermentation into higher-value platform chemicals – the basic building blocks for packaging, textiles, solvents and specialty chemicals.

Key routes under active investigation include:

  • Lactic acid: fermentation of starch-rich potato wastes and peel streams can yield lactic acid, a key building block for polylactic acid (PLA) bioplastics and for numerous food and pharmaceutical uses. When combined with on-site or nearby PLA production, this can turn a local potato processing cluster into a supplier of packaging materials as well as food.
  • Volatile fatty acids (VFAs): two-stage anaerobic systems can turn starch wastewater into VFAs (acetate, propionate, butyrate). These, in turn, can be used as feedstock for polyhydroxyalkanoate (PHA) bioplastics or other chemicals.
  • Ethanol and mixed solvents: mixed microbial cultures can produce ethanol and other solvents from glucose and starch hydrolysates in potato wastes, often alongside lactic acid or other organic acids.

Most of these routes remain at pilot or early commercial scale. The economics depend on local energy prices, policy incentives, by-product markets and access to downstream off-takers for chemicals and materials. But the direction of travel is clear: starch factories and large fry processors are being re-imagined as multi-product biorefineries, generating not only food and feed ingredients, but also chemical intermediates for materials and industry.

Bioplastics and biomaterials: potatoes as packaging

Potato peels and starch have become popular substrates for experimental bioplastics and films, precisely because they are abundant, cheap and food-grade.

Several lines of development are visible:

  • Starch can be extracted from potato peel waste, plasticized with glycerol and other agents, and cast into films that are biodegradable and, under the right conditions, compostable.
  • Blends of agro-industrial peels (including potato) can be formulated into thin bioplastic coating films with potential use in packaging, including as linings or barriers.
  • Thermally and chemically modified starch from peel streams can be used to produce structured materials – such as foams or rigid biocomposites – with tailored mechanical properties.

For the potato industry, the immediate commercial opportunity is not necessarily to become a plastics producer overnight, but to:

  • Supply high-quality, low-contaminant starch or fibre fractions from waste streams to specialist bioplastic companies.
  • Collaborate on pilots where potato-based films or coatings are used to package potato products, strengthening circular branding.
  • Position peel-based films as part of active or intelligent packaging strategies, where natural antioxidants from peel prolong shelf life or signal spoilage.

The barriers here are familiar: cost compared with fossil plastics, performance under real-world logistics, and competition with other bio-based polymers. That said, as regulations on single-use plastics tighten in many jurisdictions, niche but high-value applications for potato-based materials are likely to grow – particularly in markets where retailers and processors can capture value from differentiated, low-footprint packaging stories.

Environmental services: adsorbents, biochar and nutrient recovery

A quieter, but important, stream of work focuses on potato peel and waste as environmental tools and vehicles for nutrient recovery.

Examples include:

  • Adsorbents for phosphorus and metals: calcium-rich, ash-derived materials from potato peel, sometimes combined with eggshells or doped with iron, have been shown to adsorb phosphorus from wastewater, forming apatite-like minerals that can be recycled as slow-release fertilizers. Similar approaches are being explored for removing heavy metals or dyes from industrial effluents.
  • Biochar and soil amendments: slow pyrolysis of peel or starch residues can produce biochar, improving soil structure and water retention while sequestering carbon. Certain formulations show interesting catalytic or sorption properties, creating options for filters or reactive barriers.
  • Nutrient concentrates: some biorefinery concepts combine VFA production with recovery of ammonium and phosphate from potato starch wastewater, creating concentrated fertilizer solutions that can be recirculated to fields.

For processors under pressure to meet stricter effluent and nutrient regulations, these pathways turn compliance costs into potential product lines. For farmers, they open the door to lower-footprint fertilizers that partially replace synthetic nitrogen and mined phosphorus, while also improving soils.

The economics: from disposal cost to biorefinery logic

Valorization is not free. It requires capital, operational capability and often new partnerships. The economics revolve around several simple realities:

  • Scale matters: biogas plants, drying lines, extraction units and fermenters need a minimum throughput to be viable. This naturally favours large processors and starch factories.
  • Quality and logistics: to produce food-grade or materials-grade products, by-products must be segregated and handled hygienically from the moment they are generated. Mixed, dirty or intermittent streams collapse value and push systems back towards energy-only options.
  • Product portfolios: the most promising models treat potato waste streams as feedstock for multiple products – for example, extracting high-value phenolic compounds first, then using the remaining biomass for biogas and finally returning digestate or ash to the land.

In practice, many companies move in stages:

  1. Shift from uncontrolled discharge or basic landspreading to anaerobic digestion plus improved effluent management.
  2. Once volumes, flows and treatment performance are understood, bolt on drying, extraction or fermentation steps to capture higher-value fractions.
  3. Explore partnerships with neighbouring industries – e.g. dairy plants, breweries, municipal treatment works – to share infrastructure and risk.

For growers, the impact often depends on how contracts are written:

  • If processors treat by-products as entirely “theirs”, farmers may see no direct benefit from high-value valorization, even if it improves the overall carbon footprint of the chain.
  • If contracts recognise by-products as a shared asset – or if co-ops own part of the biorefinery – growers can capture a slice of the upside, for example through better prices, profit-sharing or access to discounted energy and fertilizers.

The circular potato economy is therefore as much about governance and bargaining power as it is about enzymes and fermenters.

Equity and participation: who gets a seat at the circular table?

From a social and territorial perspective, circular potato projects are not automatically “fair” or “inclusive”.

Several tensions are already visible:

  • Concentration of capability: advanced biorefineries are capital-intensive. Without careful design, circular value chains may simply deepen the competitive advantage of the biggest processors and input companies.
  • Labour and skills: new facilities bring higher-skilled technical jobs in operations, maintenance and lab analysis, but may reduce low-skilled work if waste handling becomes more automated. Training and local hiring policies matter if communities are to feel real benefit.
  • Territorial spillovers: biogas heat or digestate may or may not be shared with neighbouring farms. Where they are, circular projects can become anchors for regional development; where they are not, local resentment can build around “green” branding that delivers little for nearby communities.

Making the circular potato economy more equitable will likely depend on:

  • Grower co-ownership or shares in biogas plants and biorefineries.
  • Cluster approaches where multiple SMEs share infrastructure for drying, fermentation or nutrient recovery.
  • Public policies and funding programs that prioritise local participation, transparency and benefit-sharing in circular economy investments.

These questions sit squarely at the intersection of innovation and equity – which is exactly where a book on Potatoes in Transition aims to live.

What growers and processors should watch in the next decade

For industry stakeholders, several practical signals are worth tracking:

  • Regulation and carbon pricing: stricter wastewater, nutrient and climate rules will continue to push processors away from simple disposal and towards valorization pathways that deliver measurable emissions reductions.
  • Corporate climate and waste commitments: large buyers’ net-zero and food-waste pledges will translate into pressure – and sometimes co-investment – for circular solutions inside potato supply chains.
  • Technology maturation: anaerobic digestion is already mature; lactic acid and VFA platforms from potato wastes are emerging; peel-based bioplastics and specialty materials are moving from laboratory proof-of-concept to early pilots.
  • Data and traceability: documenting waste volumes and valorization outcomes will become part of ESG reporting, opening the door to new metrics, certifications and possibly new forms of value sharing.

For individual companies, a sensible starting point is often modest:

  • Quantify by-product streams with reasonable accuracy.
  • Identify “low-hanging fruit” – for example, upgrading existing feed uses, or attaching a small digester to reduce wastewater treatment and energy bills.
  • Only then consider more complex ingredient or materials projects, ideally with specialist partners and realistic timeframes.

Outlook: potatoes as anchors of circular bioeconomy hubs

If current trends continue, major potato regions are likely to see the emergence of circular hubs built around processing plants and starch factories:

  • Energy from wastewater and peel powering fryers, refrigeration and storage.
  • Nutrient-rich digestate and recovered phosphorus looping back to surrounding growers.
  • Peel-derived fibre, antioxidants and starch feeding into food, feed and materials markets.
  • Rural jobs created not just in farming and frying, but in lab analysis, fermentation, maintenance and digital control of complex biorefineries.

The risk is that these hubs become highly centralized, controlled by a handful of multinational players with limited local participation. The opportunity is that they become anchors of regional resilience – supporting farm incomes, reducing environmental footprints, and embedding more value locally instead of exporting it.

In that sense, the circular potato economy is not only a technical project; it is a political and social choice.

Whether potatoes in the coming decades are simply processed and discarded more efficiently, or become the backbone of genuinely regenerative, circular regional economies, will depend on design decisions being made now – in boardrooms, ministries, co-op meetings and farmer kitchens.

What is clear already is that the “waste” of the potato chain is anything but worthless. Handled wisely, it is one of the strongest levers the industry has to cut emissions, reduce nutrient losses, diversify income – and root the potato more firmly at the centre of a low-carbon food and materials system.

Further reading

Author: Lukie Pieterse, Potato News Today
Cover image: Credit Potato News Today

Editor/Publisher of Potato News Today: www.potatonewstoday.com. TwitterX: @potatonewstoday. LinkedIn: www.linkedin.com/in/lukie.