About Polybion

Polybion is a Spanish company with its operations in Mexico. It is a next-generation materials company using biofabrication to grow materials from bacteria. The raw material input is fruit waste, from which bacteria digest and produce a ‘skin’ of cellulose. This skin is then tanned, dyed and finished, and a backer is added for additional material structure. The company aims to produce the lowest impact alternative ‘leather’. Polybion’s CFO Alexis Gómez-Ortigoza was interviewed for this profile.

Polybion has been able to successfully genetically engineer the bacteria strains used to grow bacterial cellulose and soon new biological ways of making and processing materials will transform Celium into a more advanced material with value added properties, enhanced with synthetic biology.

Points of technical and aesthetic difference

Polybion’s Celium is a material grown from bacteria placed in an incubator where they digest fruit waste to produce cellulose in a self-organising structure: a matrix. This cellulose matrix becomes Celium after tanning and finishing processes; however, it is also a foundational structure with the potential to develop sophisticated hybrid materials. Polybion is developing its genetic engineering capabilities to include other organic molecules too. Why? Because designing materials from the atom up could generate complex networks of mixed bio-polymers that already exist in nature, thus creating materials never seen before with entirely new properties. This development is exciting but can also be expensive, complex and time-intensive.

As their technology currently stands, the Celium grown from ‘wild’ bacteria has extensive colour, embossing and textural possibilities and is produced in large sheets that are already scaled, replicable and high-yielding.

Points of impact reduction

Polybion is producing bacterial cellulose ‘leather’ on a limited industrial scale to meet demands of brand partners. When scaled up, theoretically, the low impacts demonstrated in their first LCA (more details later in this profile) are expected to decrease further. 

The Global warming potential of Celium has been calculated with multiple scenarios giving a negative figure (when avoidance of landfill of the fruit waste input is factored in), providing a figure of -0.82; up to 12.27 kg CO2 eq/m2 when no credits are applied for avoiding compost or landfill. 

Their comparative projected LCA¹ (completed in 2022) indicates that bacterial cellulose ‘leather’ has the lowest impact in all selected environmental categories compared to reference leathers (bovine leather, synthetic leather, and mushroom’ leather’). This was attributed to its low energy and chemical demands. However, the assessment did not assess the material’s durability from a sustainable life cycle perspective.

Only BASF and Stahl green chemicals that are REACH², EPA³ and ZDHC⁴ compliant are used in the Celium process. Furthermore, from December 2022, the entire Celium process will be conducted under one roof, at their headquarters.

Disruption potential and route to disruption

Celium’s potential for disruption appears broad. The market for animal hides exceeds ten billion sq. ft per year, and there is rising consumer demand for lower-impact and vegan alternatives, which Celium addresses. It is also cost-competitive because fruit waste (the raw material) is cheap and abundant.

There is a question, though, regarding Celium’s long-term material performance as it is untested in extended use. Another question is about its biodegradability due to the PU coating and the fabric backing. Although the backing adhesive is non-synthetic and safely biodegrades, some brands, according to Gómez-Ortigoza, request an rPET backing because it results in a lower overall LCA impact rating (and perhaps cost?) compared to when a plant-based material backer is used.

This admission demonstrates the mixed motivations of brands looking to reduce impacts, but only within specific phases of the material and product life cycle. This revelation may not be a significant barrier to Celium’s market disruption potential, but whether it is or not may be determined by the expectations and motivations of brands seeking such next-gen materials.

Route to commercialisation

Polybion’s majority of Cap Ex is in their three incubators (at the cost of $1.1M each), bioreactors (fermentors) and trays for material growth. In addition, they have just invested $125,000 in tanning and finishing equipment to be installed in December 2022. Additional inputs are energy, chemistry and backing materials. 

In terms of their route to commercialisation, after a Series B raise in 2023, they will take all three incubators online, each producing 370,000 sq. ft, with a total capacity of 1.1M sq. ft of Celium per year, by 2024. 

Comparisons/Limitations 

The CFO points out two known material limitations: flexibility and relatively low tear strength⁵.

“We are working on [improving Celium’s] flexibility through the tanning process [already]”, he says. The tear strength relates to the material composition and structure. The Polybion team believes that further developing the cellulose matrix could solve this problem and alleviate the need for the fabric backer. This places Celium in a comparable position to Mirum, which can be material-backed according to performance requirements.

Another limitation of Celium is the requirement of a finishing solution that contains 1% polyurethane (PU) to achieve the waterproofing and durability needed. As far as Gómez-Ortigoza has been able to determine, there is no such solution without PU. He explained that during their research into bovine, synthetic and mycelium-based leathers, they discovered that they are all typically treated with chemical finishes containing PU. 

The PU layer on the surface of Celium is 0.04 microns in thickness. For reference, one micron is one-thousandth of a millimetre.

In comparison to fungi-derived ‘leathers’ bacterial cellulose outputs are more controllable because of the simplicity in genetically altering single-celled bacteria, compared relatively complex fungi – meaning Celium could be more predictable and ‘engineerable’ than mycelium-based leather alternatives⁶.

Barriers to success 

Polybion has brand and manufacturing partners that are not publicly declared at this stage. Gómez-Ortigoza conveyed they have partnerships that guarantee fruit-waste supply and access to additional tanning infrastructure (beyond their own facility) to cope with projected rapid expansion in 2023/4 – when their three incubators reach 1.1M sq. ft capacity (dependent on a successful Series B fundraise).

“We are trying to mix and make a material as light as cellulose and as strong as collagen, playing with life’s molecular palette.”

Alexis Gómez-Ortigoza, Co-founder and CFO, Polybion