It seems like the next new material innovation can be made from anything in our kitchen fridge. Next-gen, “sustainable” materials have touted mushrooms, bacteria, seaweed, pineapples, cacti, shrimp shells, and more as the next magical ingredient. What then, are the differences between these different raw materials or inputs? How does working with different types of inputs impact scaling, manufacturing, and the resulting material’s properties?
Using the Material Innovation Initiative’s (MII) 2021 State of the Industry Report as a starting point, this article breaks down sustainable materials into categories based on their primary ingredient: recycled polymers, mycelium, cultivated animal cells, animal byproducts, plants, and microbes. We will then discuss the differences between working with these different input categories. In Part 1 of 2 in this series, we discussed the differences in creating these materials and their resulting material properties. In Part 2 of 2, we will dive deeper into the differences in scaling and manufacturing these different material inputs.
“Our innovative technology lies in its formulations… The formulations can slot into existing manufacturing processes.”
Recycled Fibers
Recycled fibers such as recycled polyester and nylon are popular in part due to the ease with which they integrate into existing supply chains. Recycled fibers behave very similarly to their conventional counterparts, which means they can slot easily into existing manufacturing methods. Additionally, due to their popularity, the price of recycled materials has come down substantially. This makes them very accessible to be used even in lower price point products.
However, recycled fibers have many downsides as well. They perpetuate the reliance on using petrochemical-based materials which creates a very large carbon footprint. Additionally, recycled fibers are usually sourced from recycled plastic bottles. Plastic bottles can be recycled back into plastic bottles, but most textiles do not have the existing systems in place to be recycled back into textiles. This means that sourcing fibers from plastic bottles divert them from the plastic recycling cycle and into the landfill, as most textile recycling cycles are not well developed.
Mycelium
Materials made from mycelium—or the root networks of mushrooms—can be grown using solid-state fermentation or using liquid fermentation. In liquid-state fermentation, mycelium cells are grown inside bioreactors, which are established technologies already scaled for industrial use. This method of growing mycelium allows the material to be cast in a continuous liquid sheet, offering more flexibility in the size that can be produced.
Mycelium grown using solid-state fermentation is often grown in a tray. A sheet of mycelium-based leather as large as a cowhide can grow in up to two weeks— much faster than the years it takes to grow a cow. It is then later turned into leather alternatives through proprietary processes. It is important to be aware that some brands’ post-processes still use plastic coatings to achieve the handfeel and durability expected of animal leather.
The main method of scaling mycelium that is grown using solid-state fermentation involves stacking these trays of mycelium into “vertical farms.” While theoretically, it is possible to have a sheet of mycelium as large as any tray that can be built, it still means that larger quantities require larger factories to scale. Some mycelium companies are currently committing to building their own manufacturing facilities to accommodate the in-house manufacturing of their own materials using their own equipment. The specificity of these facilities and these processes could limit the flexibility of future operations.
Cultivated Animal Cells
Materials made from cultivated animal cells grow animal leather in a lab setting. Lab-grown leather can be produced in a smaller facility and in a much shorter time frame than conventional animal leather. It eliminates the need for the pastures and feed to grow a cow for its leather, but may require more specific equipment.
Using cultivated animal cells uniquely creates leather alternatives that exactly resemble animal leather at the cellular level. This comes with both pros and cons. Since the resulting material behaves the same as animal leather, it can work with existing leather treatment processes, such as tanning, dyeing, printing, and embossing. Brands would not need to greatly alter their existing production systems.
Unfortunately, many of these existing leather post-processing techniques, including tanning and dyeing, still use harmful chemicals that are not sustainable in their own right. Some lab-grown leathers can be tanned using much fewer chemicals than conventional processes, though may still rely on them. Additionally, a common nutrient-rich feedstock used for cultivated animal cells is fetal bovine serum, which is obtained by killing a pregnant cow. While there is progress on plant-based feedstocks and other alternatives, these solutions have not yet been scaled.
Animal Byproduct
Material innovations derived from animal byproducts use animal-derived raw materials that would otherwise go to waste or would be harmful to the ecosystem. These include using shellfish waste from the fish oil industry or using invasive species as raw materials. While these new leather alternatives do perpetuate the use of animal-derived raw materials, they also avoid using the large number of resources that raising cows requires.
Unfortunately, however, the inputs themselves cannot be scaled. Shell waste from making fish sauce is limited by the number of shellfish caught and discarded in the process. The use of invasive species is limited by the invasive numbers of the species. These materials are a good temporary solution, but only for as long as the need to consume these animal byproducts continues.
Plant-Derived
A large category of material innovations is derived from plants. These can range from using agricultural byproducts such as corn to virgin feedstocks such as natural rubber, cork, apples, and cacti. Plant matter is everywhere, making it a plentiful feedstock source. Additionally, the diversity in plant matter allows for many properties to be achieved from different combinations of plant-based additives.
These types of materials reduce the reliance on animals and fossil fuels. However, with such a wide range of plant-derived materials, it is important to ensure that the beneficial aspects of using plant-based feedstocks are not negated by using coatings or curatives derived from fossil fuels.
Additionally, it is important to monitor where the plant matter is sourced from. The end goal should be to source plant inputs that use existing agricultural waste, do not cause food stress, or are sustainably farmed. Depending on the material, there remains the risk of using plant matter that is not sustainably farmed or contributes to deforestation.
Microbe-Derived
Microbe-derived materials are easily scalable due to their reliance on infinitely renewable nanocellulose. There is even the possibility of having microbes self-assemble the final garment or accessory. Scaling nanocellulose in this way is similar to producing mycelium in stacked trays on vertical farms. While this avoids the reliance on petrochemicals and animal farming, it still means that creating microbe-derived materials may require large, proprietary factories.
While materials solely derived from microbes are conceptually possible, they can be difficult to execute consistently. Bucha Bio has encountered firsthand the challenges of air bubbles and material inconsistencies created by bacteria. It can be difficult to create larger sheets without structural issues and it is impossible to create the same sheet twice. Additionally, it is important to know that many microbe-derived materials still require petrochemical coatings to prevent them from drying out and becoming brittle.
So, What About Bucha Bio’s Scaling Plan?
Bucha Bio’s manufacturing benefits from using both plant and microbe-based inputs. Our innovative technology lies in its formulations, rather than any special equipment needed to produce its materials. This means that manufacturers do not need to acquire any new equipment when producing Bucha Bio’s materials. The formulations can slot into existing manufacturing processes.
As Bucha Bio works on scaling strategies, we can then focus on partnerships with third-party manufacturers, rather than building our own manufacturing facility. Partnering with third-party manufacturers allows Bucha Bio the flexibility to produce materials anywhere in the world— especially in factories local to different brands’ manufacturing facilities.
This flexibility in manufacturing location is paramount for efficiently working with brands and their existing supply chains. However, Bucha Bio notes that there are also downsides to this strategy. Using many different ingredients and reagents—which helps to create a highly customizable material—can also cause complexity in the supply chain.
As material innovators continue to work with everything but the kitchen sink, it becomes increasingly important to understand the pros and cons of each type of material. No one material is going to save our planet single-handedly just yet. However, by recognizing the strengths and weaknesses of different materials, we can make the most responsible decisions for different material needs.
Note: Bucha Bio rebranded to Rheom Materials in January 2024 to better reflect their process and offerings. The new name combines the Greek word "rhéō" (meaning "flow") and "form," describing how a melt-extruder works, where the biopolymers flow into place and then solidify, or form, the final product.
