Bio-based ≠ Circular: Challenging Green Chemistry Narratives

Photo by Chokniti Khongchum

From biodegradable plastics to bio-fibres, these bio-based materials are considered greener because they can reduce fossil fuel use and improve soil carbon dynamics, thanks to their reduced carbon footprint and enhanced biodegradability potential. These bio-based materials offer new services and functionalities, reveal lower levels of toxicity, improve biodegradability and recyclability. Together, these factors contribute to the perception that “bio-based” means “better”

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However, these benefits depend on lifecycle conditions that are often not given enough consideration. Bio-based should thus not be confused with being fully circular. There needs to be rigorous standards and lifecycle management, or the potential that bio-based materials possess risks being reduced to mere greenwash, rather than being an applicable solution.

Land Use Challenges

Exploring feedstocks, such as corn, algae, and soybeans, can increase biomass availability for a circular bioeconomy. However, simply replacing fossil feedstocks with biomass does not ensure that waste management is properly solved, as it depends on the source of the feedstock to determine whether it can create new sustainability issues. Agricultural land once used for food production is increasingly repurposed for bioplastics, bio-fibres, and biofuels. While it is intended to reduce greenhouse gas emissions (GHG), this raises concerns over food security, lack of land availability, and higher food prices.

Cultivating these bio-based materials requires significant land and water resources. An example is producing a single cotton T-shirt. This bio-based fibre garment requires 2,700 litres of water. Life Cycle Assessment (LCA) studies have found that intensive agriculture for bioplastics cultivation can lead to eutrophication from pesticide and fertiliser use, as well as increased levels of existing toxins. Using crops as feedstocks may cause direct and indirect land use change, which causes GHG emissions that can offset the benefits of biogenic carbon capture, creating even longer-term environmental issues.

Even when biomass is reliably and sustainably sourced from forestry or agricultural waste, scaling up its production requires careful management to avoid soil erosion, biodiversity loss, and excessive water use. Furthermore, feedstock selection and land use trade-offs determine whether bio-based materials reduce or increase environmental challenges. LCAS must include transparent data on land use emissions, water use, food security metrics, and the end-of-life of materials to avoid creating further burdens on the environment and on human and animal life.

End-Of-Life Pathways Challenges

The entire lifecycle of bio-based materials, including how they are managed at end-of-life, determines exactly how sustainable they are. Biodegradation requires specific and controlled conditions in industrial composting facilities or digesters. However, there is a lack of industrial composting facilities, and globally, there is an infrastructure scarcity due to the existing waste management infrastructure not being originally designed to handle bioplastics. In the EU, only a small share of municipal waste is treated in industrial composting facilities. As a result, most biodegradable plastics do not encounter the conditions required to break down effectively.

This leads to biodegradable plastics not fully breaking down and leaving behind harmful micro- and nanoplastics. These plastics then interfere with waste management systems, including composting, incineration, landfilling, and recycling. In anaerobic conditions, where oxygen is absent, bio-based materials can decompose slowly, releasing methane and contributing to CO₂ emissions in the air. Landfill functionality is limited due to the accumulation and decomposition of biodegradable plastics combined with other biomass waste, while exorbitant biomass use may weaken CO₂ emission reduction.

The use of bio-based materials adds complexity to recycling pathways, due to the combination of different polymers and additives, making both mechanical and chemical recycling harder to achieve. Each material requires different recycling processes, and mixing them can lower the quality of recycled products. Chemical recycling of bioplastics requires high levels of energy and chemical inputs, potentially harming the environment and posing health risks to humans and animals. Mechanical recycling remains limited due to infrastructure gaps. A standard end-of-life treatment option, such as incineration, wastes recoverable and recyclable materials, like fertilisers and pesticides. This reduces the material recovery potential and is inconsistent with circular economy objectives.

Without proper collection, sorting, and treatment systems, bio-based materials risk adding more complexity to waste management rather than reducing it. Bio-based value chains involve additional steps than fossil-based chemical production. The biomass pre-treatment and the further purification of the targeted chemicals face several technical barriers on a commercial scale. Poorly designed waste-handling systems increase collection and sorting costs. They also reduce profits and make waste treatment less efficient. As a result, these factors reduce the circularity of bio-based materials, as claims about the biodegradability of these materials can be misleading when industrial conditions are not fulfilled.

Substantial and harmonised investment in waste infrastructure is required if we are to expect bio-based materials to fulfil their promised objectives.

Persistence Challenges

Although bio-based products are marketed as biodegradable, many bio-based plastics and fibres are not more sustainable than fuel-based chemicals. There are high amounts of plastic and microplastic waste in rivers, oceans, and marine ecosystems due to waste mismanagement, and end-of-life biodegradable plastics do not degrade efficiently in nature, even after three years. Current standards and tests cannot reliably predict biodegradability in the ocean, soil, or open air, nor do they account for possible ecological impacts or include toxicity tests.

Textiles are an example, with bio-based and biodegradable fibres like PLA, bioplastics or wood-based alternatives, are seen as a solution for synthetic ones. While synthetic fibres, which come from fossil-based feedstocks, present end-of-life persistence and cause environmental issues, biodegradable ones can also do the very same. The impacts of bio-based materials and biodegradable fibres depend on feedstock sourcing, processing chemical and production system, energy mix in processing, and end-of-life fate. Recent ecotoxicology studies show that some bio-based microfibers, once released into the environment, may cause ecological damage comparable to, or even greater than, petrochemical microfibers.

LCAs must include toxicity endpoints and shedding during use, not just carbon balances, when comparing fibre types. These plastics require specific conditions to degrade properly, which are usually not found outside of controlled environments. Through a rigorous, evidence-based evaluation of lifecycle trade-offs that support loop closure in end-of-life plastics, these existing challenges may be addressed. The Safe and Sustainable-by-Design (SSbD) framework should be considered because it ensures that new chemicals and materials are safe throughout their entire lifecycle and break down into non-persistent, non-toxic residues. Otherwise, the potential sustainable benefits of bio-based products risk becoming voided, minimising harm in one area and creating new challenges in other areas.

The EU’s chemical sector emits annually 60 million tons (Mt) of carbon dioxide, with 80% of the chemicals produced being classified as hazardous to human health under the CLP Regulation. While recent research shows that bio-based plastics could reduce emissions and toxicity, only 3% of the EU’s chemical production is bio-based. Scaling up bio-based chemicals in the EU also has issues. There is a limited amount of bio-based resources available, there is cost competitiveness against fossil feedstocks, and many bio-based technologies are still in their early stages of development.

Persistence and toxicity are key to SSbD frameworks, so that bio-based products do not just replace fossil-based ones with different but just as damaging consequences.

Standards Preventing Greenwash

Standards and regulatory frameworks are essential to distinguish authentic sustainability from greenwashing. For example, providing clear definitions of what it means to be “bio-based," “biodegradable,”“circular"and “compostable” reduces the spread of misleading claims. These terms may be used interchangeably, creating confusion and diminishing the importance, meaning, and distinction of each term. For example, harmonised sustainability schemes like the EN16751 standard in Europe focus on bio-based chemicals, bioactive substances, and materials instead of food, energy, or feed.

Driven by the European Green Deal, the SSbD framework highlights minimising hazards throughout a product’s entire lifecycle in order to ensure human and environmental safety against harmful chemicals and ensure resource efficiency and circularity. Stronger Environmental, Social, and Governance (ESG) reporting requirements, including external audits, can reduce opportunities for exaggeration and misrepresentation that promote greenwashing.

Without harmonised standards, consumer trust is undermined, and industry incentives are weakened. Greenwashing misleads environmentally conscious buyers and can also affect the meaning of what it is to be sustainable. Greenwashing can lead to waste mismanagement in the environment and erode public trust in government action. Companies that exaggerate the benefits of their biodegradable products risk damaging their reputation, as well as providing opportunities for other companies to pursue similar misleading tactics against consumers.

Effective governance requires stricter and more coherent regulatory policies that penalise false or even misleading declarations of environmental performance, require transparent science-based reporting by independent entities, and harmonise definitions. Companies will be pressured by regulatory policies to implement genuine sustainability policies and demand transparency in ESG reporting. There needs to be a push for public awareness of environmental protection, as well as an encouragement for society to become more environmentally responsible. These recommendations will reduce the opportunity for greenwashing.

Final Thoughts

Debate continues over whether biodegradable plastics represent a genuine solution or simply a form of greenwashing to appear environmentally friendly. Bio-based does not equal circular. Their biodegradability is limited by physical and chemical characteristics, limiting their sustainability. In addition, land use pressures, inadequate end-of-life pathways, and persistence of these materials in the environment reveal that “bio” is “better“ is a form of greenwashing. There needs to be a clear, comprehensive definition of biodegradability that addresses all aforementioned factors, as well as clear standards, science-based reporting, and rigorous lifecycle assessments to ensure that bio-based products can be genuinely sustainable.

The upstream of bio-based chemicals and plastics can be designed to ensure better degradability, recyclability, and composability. To do so, there needs to be a scale-up in infrastructure investment, harmonised standards, and SSbD principles. Without proper management, bio-based products risk continuing to cause environmental impacts and becoming another form of greenwash, rather than fulfilling their potential to contribute to a circular economy.