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Abstract

Biomaterials are emerging at the forefront of the circular economy shift. Biomaterials, or bio-based materials, refer to raw materials derived from plants, such as cotton, silk, or wood, and are commonly utilized in our daily lives, appearing in items like packaging, clothing, and furniture. However, a noteworthy development in recent years involves leveraging biomaterials as substitutes for fossil-based materials, particularly in plastic production. Termed “sustainable biomaterials,” these contribute to the creation of a specific kind of bioplastic, marking an innovative shift away from traditional oil-based materials. Derived from living organisms, biomaterials are celebrated for their renewable, biodegradable, and environmentally-friendly attributes. While each early-stage material innovation demonstrates enhanced sustainability compared to its conventional counterpart, a key challenge remains: transitioning these innovations from niche, localized solutions to globally accepted standards, without losing focus on sustainability.

Biomaterials can offer environmental benefits in many ways, including carbon sequestration through biomass production, energy efficiency due to improvements in manufacturing, lower environmental impact and biodegradability. But before we accept biomaterials as a silver bullet to sustainability challenges, understanding how these future materials help or harm the environment is critical. This case explores the advantages and limitations of biomaterials in various industries through some of the most popular biomaterials, including bioplastics, biofuels (or sustainable aviation fuels) and alternatives to concrete.

Main Highlights

● The modern world is eagerly searching for sustainable alternatives across sectors that align with the concept of a circular economy. Biomaterials offer a promising solution in this as they are derived from living organisms and therefore renewable.

● Biomaterials are generally regarded for their biodegradable, renewable, and eco-friendly potential. Popular examples of biomaterials include bioplastics, biofuels, and alternatives to concrete.

● Each small-scale prototype of a new biomaterial intends to be more sustainable than its traditional counterpart. However, the challenge lies in scaling these innovations sustainably from localized solutions to globally accepted standards.

● Biomaterials can offer environmental benefits in many ways, including carbon sequestration through biomass production, energy efficiency due to improvements in manufacturing, lower environmental impact and biodegradability.

● Bio-based solutions can be unsustainable due to high dependence on agricultural resources, competition with food production and/or high water use.

● Biomaterials include a wide range of solutions that may or may not add significant environmental benefits over their traditional counterparts.

● Different products offer very different functional and environmental advantages and transfer responsibility on to the user to select the right product for a project.

● Policy interventions play a pivotal role in encouraging adoption by customers and determining the market success of biomaterials.

● Biomaterials can have economic consequences as they may disrupt traditional industries. This could lead to job losses and necessitate a paradigm shift in workforce training.

Case Overview

In the face of environmental crisis and resource depletion, the modern world is urged to innovate, leading to an increased focus on sustainable alternatives. One of the key frameworks driving this paradigm shift is the concept of a circular economy, where resources are recycled and reused without wastage. At its core, a circular economy aims to minimize the resource burden in manufacturing products, to keep resources in use for as long as possible through built-to-last designs, and to recover and regenerate materials at the end of a product’s life.

Biomaterials have emerged as a potent ally in this cause, primarily due to their biodegradable, renewable, and eco-friendly potential. Biomaterials, i.e. materials derived from living or once-living organisms, align perfectly with the concept of a circular economy because they can be cultivated naturally and returned to the environment without harmful effects. However, biomaterials that undergo processing may not consistently exhibit biodegradability, and their combination with other materials, such as glass or metals, can impede the ease of recyclability. Also, the heightened production of biomaterials has the potential to place strain on natural resources and foster reliance on non-biological substances, such as agrichemicals, which can have significant adverse effects on the environment. Through the following examples of biomaterials, this case explores the advantages and limitations of biomaterials across various industries.

1. Bioplastics

One of the most popular areas of innovation is in the development of bioplastics. Plastics, whether derived from petrochemicals or bio-based chemicals, consist of polymers formed by bonding together polymer chains, which, in turn, originate from smaller units called monomers. Unlike conventional plastics made from petroleum, bioplastics are derived from renewable biomass sources, for example, fast-food packaging made from algae, straw, or vegetable oils; cutlery made from corn starch; plastic bottles made from sawdust; nursery plant pots from recycled food waste; and even bioplastics made from dead insects.

Oftentimes, when developing methods to convert natural products like glucose into degradable polymers, these compete with resources vital for food, fuel, construction and transportation. To overcome this, researchers have explored using waste from farming black soldier flies, whose larvae are utilized for animal feed and waste breakdown. Chitin, a sugar-based polymer found in flies, serves as a significant component strengthening the exoskeleton of insects and crustaceans, such as shrimp and lobster, as well as in the extremely thin, transparent membranes of dragonfly wings and the soft tissue of fungi. Researchers suggest that chitin extracted from flies appears purer than that obtained from crustaceans, alleviating concerns related to seafood allergies. Chitin, the second most abundant biopolymer following cellulose, is commonly extracted in large quantities from abundant waste produced by the shellfish industry. This underscores how biopolymers and the living systems they form excel not just in efficiency and diverse functionalities but also in their capacity for renewal, surpassing human engineering.

The production process of these plastics itself incorporates sustainable practices as it can involve use of waste materials and/or CO2 absorption through the culturing of feedstocks (such as algae). However, not all bioplastics are equal. The cultivation of the crops used to produce bio-based feedstocks, the extraction or fermentation of these feedstocks to obtain the necessary monomers, and the subsequent polymerization processes all contribute to the overall energy requirements. Also, the need for specialized machinery for processing and forming bioplastics can add to the energy demands of the production process.

However, market data analysis by European Bioplastics shows that packaging remains the largest field of application for bioplastics, constituting 48% of the total in 2022–an ideal scenario considering the predominance of single-use packaging, for which reverse logistics solutions are unfeasible. Despite robust recycling infrastructure in European countries, plastic recycling rates are estimated at 41.5%, meaning nearly 60% of recyclable plastics are discarded. With the fast-increasing rate of production and consumption of bioplastics, understanding how these future materials help or harm the environment is critical.

Image: Illustration of various uses of bioplastics in everyday life.

Biodegradable plastics have a clear advantage of minimizing the health and environmental hazards from polluting microplastics. Often mistaken to be the same thing as biodegradable plastics, bioplastics encompass a wide range of products that may or may not be able to biodegrade in natural environments. In fact, some biomass-based plastics have the same chemical structure as fossil-based plastics and do not help combat any downstream waste and pollution challenges of plastics. While other bioplastics such as PLA are biodegradable, the concept of biodegradation is not as straightforward as many believe. Biodegradable and compostable plastics are shown to be biodegradable in lab conditions, which can often only be recreated in industrial composting systems. This waste infrastructure may not be accessible in many parts of the world or even in all parts of a developed country, leaving large areas unable to bridge the gap between biodegradable and biodegraded.

Some of the most sustainable bioplastic solutions are seaweed-based bioplastics produced by companies like Notpla and FlexSea. These products are designed to be home-compostable, disappearing within 4 to 6 weeks in natural conditions. The use of seaweed as a raw material enhances sustainability further, as it doesn’t compete with food production or other land-use needs and doesn’t require freshwater. In addition, FlexSea has innovated its manufacturing processes to be low-energy (utilizing extrusion-based biomanufacturing) and zero-waste by making use of off-cuts.

Image: Seaweed-based bioplastic in use

While bringing elements of sustainability into a plastic-driven world, even the most sustainable bioplastics encourage an unsustainable use-and-throw culture. They also require waste management infrastructure to handle their end-of-life. In the best-case scenario, bioplastics would be made from waste materials (as seen in seafood-waste-based Marinatex), used only in situations where no superior alternative exists, and composted after use. Presently, even the most advanced products fail to meet all the criteria and require a policy change to regulate their usage.

2. Biofuels

Transport accounts for 21% of global greenhouse gas emissions. Road transport—personal transport and freight—is responsible for three-quarters of the emissions, while aviation and shipping contribute 11.6% and 10.6%, respectively. Electric vehicles provide a feasible alternative to road transport, but aviation and shipping rely on liquid fuels for long-distance transport. Biofuels, particularly Sustainable Aviation Fuels (SAF), have garnered significant attention over the past few decades as potential alternatives to traditional fossil fuels. Derived from plant matter and agricultural waste, SAF is considered a sustainable alternative to petroleum with many benefits and challenges.

Innovation in SAF over the past decades has changed both the efficiency and the eligibility of products that qualify as SAF. Progress from first-generation to fourth-generation biofuels represents a journey towards greater sustainability and efficiency. First-generation biofuels were based on food crops (such as corn) and involved conventional fermentation to yield ethanol. Second-generation biofuels utilized non-food crops and forestry waste products, thereby minimizing the competition with food production, and used enzymatic processes to convert cellulose to ethanol. A benefit of utilizing agricultural and forestry waste for biofuel production is that the waste is managed and doesn’t emit greenhouse gases through rotting. In comparison, third- and fourth-generation biofuels make use of algae and certain microbes that naturally produce hydrocarbons. Compared to land crops, algae cultivation generates more biomass, can aid in carbon capture, and does not require significant land and freshwater resources, all of which drastically improve the environmental footprint of these fuel alternatives. Hydrocarbons produced by algae and other microbes also bypass resource- and energy-intensive steps of biomass breakdown and processing.

Image: Evolution of biofuels through each generation

Fourth-generation biofuels aim to be carbon neutral or even carbon negative, thereby influencing the criteria for ‘Sustainable Aviation Fuels’ to meet higher standards. These fuels are required to adhere to sustainability criteria, including lower lifecycle carbon emissions, limited fresh-water requirements, no competition with food production, and no contribution to deforestation. Currently, SAF products emit up to 80% less carbon across their lifecycle than traditional fuels, taking into account emissions/carbon drawdown during the growing, processing, and combustion phases. In addition, SAF contain fewer impurities than traditional fuels, resulting in lower particulate matter emissions that are harmful for human health.

Image: Components of typical well-to-wing LCA for fossil-based jet fuel and biofuel

Fourth-generation biofuels are similar in their chemical composition to traditional fuels and can be used as a pure substitute. The 100% use of SAF has the potential to reduce emissions by up to 94%. However, SAF is currently blended with tradition fuel at 10% to 50% to mitigate the risks associated with adopting new fuels, implying a continued demand for traditional fuels in the current model.

Companies around the world are investing in biofuels including Neste (Finland), Shell (Dutch), Gevo (US), Enerkem (Canada), Novozymes (Denmark), Abengoa (Spain), Qantas (Australia) and many more. Yet, scalability remains one of the biggest challenges in the sustainable implementation of biofuels. Even though algal biomass efficiently sequesters carbon from the atmosphere, immense infrastructure is required to produce it at the rate at which it is consumed.

3. Alternatives to concrete

Concrete, a staple in the construction industry, has long been applauded for its strength, durability, versatility and cost-effectiveness. It uses widely available ingredients that quickly harden into a stone-like mass. It can be poured into molds of any shape, allowing for diverse architectural and structural designs. And though many projects can utilize alternatives to concrete without jeopardizing function or safety (such as non-structural walls and driveways), its cost-effectiveness makes it difficult to replace.

However, concrete production, specifically portland cement production, is responsible for approximately 8% of global emissions, primarily due to the energy-intensive production process of cement and CO2 emissions during hardening. It also lacks an end-of-life solution, posing a hindrance to the implementation of a circular economy in the construction industry. This necessitates the search for eco-friendly substitutes to concrete.

Alternatives to cement integrate sustainability through one or more of the following ways:

Resource Conservation – Alternatives like geopolymers require less limestone and other natural resources than traditional cement. This conserves these resources and reduces the environmental impact of their extraction. Geopolymers can offer comparable or even superior strength and durability to traditional concrete.

Use of Waste Materials – By incorporating waste materials into their recipe, some concrete alternatives utilize waste from other industries and are able to divert waste from landfills. For example, fly ash which is a byproduct of coal combustion, and slag which is a byproduct of steel production. Using these materials reduces waste and minimizes the environmental footprint of extracting virgin materials.

Carbon Sequestration – Some innovative cement alternatives offer the potential to sequester (or capture) carbon dioxide by either linking with CCU projects or incorporating sustainably grown biomass.

Enhanced durability – Certain cement alternatives provide improved resistance to corrosive agents, thereby increasing the durability and lifespan of structures.

Energy efficiency – Some cement alternatives offer better insulation properties than traditional cement. This can lead to more energy-efficient buildings, cutting down energy consumption for heating or cooling, and thus reducing the associated carbon emissions.

Biodegradability – Some cement alternatives are based on natural and biodegradable materials, and can be returned to the earth without leaving harmful residues. These products ensure a perfect closed-loop lifecycle.

By substituting concrete with the most suitable alternative, it’s possible to reduce the environmental footprint of construction without compromising on the safety, function, or aesthetic appeal of a structure.

Two popular alternatives to concrete are Hempcrete and self-healing concrete.

Hempcrete is a bio-based material. As it sequesters carbon through the growing of biomass, Hempcrete is a carbon negative product. The product is more insulating than concrete and reduces energy consumption in buildings, furthering its sustainability impact. On the other hand, the blocks are cast-on-site but less versatile than concrete. The construction method is different from modern conventional construction and requires retraining of builders in the industry to be able to use the alternative. Bio-based products similar to Hempcrete include Grasscrete and Miscrete.

Image: Illustration of a typical bio-based cavity wall assembly made of hemp concrete

Self-healing concrete is a technological innovation based on the discovery of lime-producing bacteria. It integrates certain species of bacteria in the cement mix that, when exposed to water, generate lime and are able to repair a crack in the wall. The product enhances the sustainability profile of concrete mainly by reducing repair costs, but does not create a circular solution. The impact of this solution on overall durability and health impacts of building users is also yet unknown.

New alternatives have to go through rigorous tests to be certified, and yet find it difficult to gain traction and be adopted by customers. This is understandable as the various pros and cons of different alternatives over concrete put the onus on the user to judiciously select the right material for the right application. Slower adoption and the resulting smaller markets for each product add to the challenge as these solutions are unable to reach economies of scale and continue to be more expensive than the traditional product.

Image: Innovator Hendrik Jonkers with a sample of self-healing concrete

Impact Statement

The potential of biomaterials in shaping a sustainable future is undeniable, extending beyond their physical properties to encompass broader implications in line with key circular economy principles. Positioned as potential replacements for many non-renewable resources, their promise is significant.

Nevertheless, the road to integrating biomaterials into our everyday lives demands a careful and well-researched approach. Biomaterials encompass a wide range of solutions that may or may not add significant environmental benefits over their traditional counterparts. For example, within the realm of bioplastics, bio-based alternatives sharing the chemical composition of ordinary plastics pose downstream challenges akin to traditional plastic, including microplastic pollution and lack of proper waste infrastructure. At the same time, the imperfect nomenclature used for a range of new products makes it difficult for the average user to assess a product’s sustainability metrics. Similarly with alternatives to concrete, different products offer very different functional and environmental advantages and transfer responsibility on to the user to select the right product for a project.

Bio-based solutions, while theoretically less resource intensive and natural, may also not be sustainable due to high dependence on agricultural resources. Unsustainable farming or overreliance on a single crop can lead to environmental imbalances like deforestation or overuse of water. The early generations of biofuels, based on crops that competed with food and other land uses, exemplify these challenges. In contrast, Fourth-generation algae-based biofuels demand massive infrastructure to reach the intended scale but offer the potential to draw down carbon. In other words, a project’s overall environmental and social impact depends on its exact design and implementation.

Systems Perspective

Biomaterials, encompassed by the examples discussed here, cut across various industries and economies, with each small-scale prototype of a new material aspiring to be more sustainable than its traditional counterpart. However, the challenge lies in scaling these innovations sustainably from localized solutions to globally accepted standards. This scaling process involves not only production, but also a meticulous analysis of feasibility and impact.

While biodegradability is often inferred in all biomaterials, this assumption is not universally accurate. The term is also associated with environmental friendliness, yet it’s crucial to understand its nuances. A material labeled as biodegradable doesn’t necessarily mean it will break down efficiently in every environment. The conditions and settings under which these materials decompose can vary widely, impacting their overall sustainability.

Policy interventions play a pivotal role in determining the market success of biomaterials. For an eco-friendly alternative to gain traction among consumers, supportive policies and regulations are key. Europe’s rapid transition from plastic cutlery to sustainable alternatives is a prime example of policy change influencing adoption of sustainable alternatives.

However, as we pivot towards a biomaterials-centric world, economic consequences must be considered. Established industries heavily reliant on traditional materials could face disruptions, potentially leading to job losses and necessitating a paradigm shift in workforce training and skills. As with any significant transition, it is essential to balance innovation with the socio-economic implications it brings.

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