Material Innovation / Tandem Repeat Interview

Collection: Sea Change

Combining Protein and Lyocell Using Chemistry and Biology: Material Innovation Ready to Expand

US-based deeptech innovator Tandem Repeat, a climate-positive smart textiles company, has developed Procell, a revolutionary patented fermentation microbial process that transforms proteins into valuable products, including fibres and nonwovens which are a less toxic alternative to plastics. Leading inventor and Penn State Huck Endowed Chair of Biomaterials Professor Melik Demirel simplifies the tech and his plans for the future.

Richa Bansal

7 February 2025

6 minutes

Long Story, Cut Short

The next phase is the building phase, which will require $100 million, and Tandem Repeat is currently awaiting funding from the government or private investors.
The lack of a domestic spinning industry in the US makes it hard to partner with established manufacturers to produce new bioengineered fibres.

Tandem Repeat stems from a 15-year research effort, which includes 8 years in the lab and 7 years in industry, dedicated to creating protein-based solutions materials.

Research & Development Tandem Repeat stems from a 15-year research effort, which includes 8 years in the lab and 7 years in industry, dedicated to creating protein-based solutions materials. Tandem Repeat

Tandem Repeat’s Professor Melik Demirel is joined by Dr Benjamin Allen and Dr Gozde Senel-Ayaz in trying to help bring their innovative technology into reality.

Tandem Repeat’s project focuses on the fabrication sector, specifically on developing advanced fibres and textiles that meet the rigorous demands of military applications. This initiative supports the US Department of Defence’s mission to safeguard America’s ability to produce essential materials domestically, particularly in the face of challenges such as natural disasters, warfare, and climate change. With a $1.5 million award from the Department, the company is set to scale its innovative technology, contributing to a more resilient and sustainable defence supply chain.

Partnering with Arctos Technology Solutions, an established aerospace and defence contractor, this grant is part of the DoD's Distributed Bioindustrial Manufacturing Programme, which aims to bolster domestic supply chains, reduce logistical complexities, and promote sustainable solutions for defence.

Tandem Repeat’s breakthrough lies in its ability to harness proteins to create fibres that are both durable and environmentally friendly. With this funding, the company is set to expand its production from a pilot scale of 500 kg to a commercial scale of 1,000 metric tonnes, addressing the growing demand for sustainable materials in both defence and commercial sectors.

Protein biomanufacturing entails largescale production of proteins using living cells such as bacteria or yeast. This process encompasses synthetic biology, strain and fermentation engineering, and downstream processes. To optimise biomass fermentation, it is essential to carefully control parameters such as temperature, pH, nutrient availability, and microbial strain selection to achieve high product yields, titers, and productivity, ultimately rendering the process economically viable and environmentally sustainable.

Procell’s greenhouse gas emission footprint (5.39 kg of CO₂/kg), water usage (0.52 m³/kg), and land usage (12.4 pt/kg) are lower than any natural fibre products, including cotton, lyocell, and wool.

Tandem Repeat’s Sonachic is a collection of luxury basics inspired by sweater and cardigan knitting, featuring Procell fibre made from fermented proteins. Rooted in the same style aesthetic that positioned Tandem as a favourite at fashion shows, the brand offers elegantly designed, streamlined pieces in a neutral colour scheme. The selection includes sweaters and cardigans made from Procell fibre.

texfash.com: You have a background in materials science and engineering. So, was Tandem Repeat the natural next step?
Melik Demirel: I have a background in biotechnology and materials science. My first scientific article on protein engineering and design was published in 1996. Following that, I focused on developing engineered proteins for human applications to replace environmentally harmful plastics. Materials science is the ideal field for tackling this challenge. Tandem Repeat stems from a 15-year research effort, which includes 8 years in the lab and 7 years in industry, dedicated to creating protein-based solutions materials.

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The scope and canvas for materials science is huge. What made you settle down on textiles/fibres?
Melik Demirel: At Tandem, we investigated several avenues, from medical uses to cosmetics and adhesives. However, we faced challenges: the medical realm had a complicated regulatory pathway, the cosmetics industry was overly focused on marketing, and adhesives provided low profit margins with limited options. In contrast, the textile market is worth $3 trillion annually. A start-up aspiring to achieve just 1 percent market penetration within five years offered a strong proposition to venture capitalists. Our goal was to convert our new, nature-inspired material into fibre.

Which came first: the concept of Squitex, or that of Tandem Repeat as an organisation that would subsequently work on climate-smart textiles?
Melik Demirel: Tandem Repeat was initially developed because nature employs gene duplication to form complex proteins by repeating unique tandem blocks like collagen, keratin, elastin, silk, squid ring teeth, and others. The name Squitex, blending squid with textile, was introduced later, following the Tommy Hilfiger award we received in 2019. Currently, we have adopted Procell, combining protein and lyocell using chemistry and biology; this new name represents proteins generated through biomass fermentation, unlike Squitex, which emphasises precision fermentation. Biomass fermentation supports large-scale production of proteins, while precision fermentation offers unique features such as self-healing and thermal switching, which we have documented in high-impact publications.

Tell us more about Squitex. How long did it take you and your organisation to work on it? What was the roadmap you had chalked out? And yes, what were the roadblocks you faced?
Melik Demirel: The production of the new product involved biofermentation to generate protein pulp, which was subsequently transformed into fibre. It’s essential for these processes to be integrated and operate simultaneously. However, this has been difficult domestically due to the decline of the American textile industry. Past efforts to manufacture bioengineered fibres in the United States fell short because they struggled with the spinning stage and were unable to produce fibres at a competitive cost. The lack of a domestic spinning industry made it hard to partner with established manufacturers to produce the new bioengineered fibre. This highlights the challenges of developing an advanced biomanufacturing sector when foundational production capabilities are no longer in place.

Your website says: "Squitex is produced at lower costs using carbon-negative methods to reduce global warming effects." Please give us an idea about the costs, and also the carbon-negative methods.
Melik Demirel: We explored various options, including CO2-based fermentation and utilising corn for plant molecular farming. Despite the success of our initial research and development, which resulted in patents, we determined it was not economically viable to further pursue these projects.

Professor Melik Demirel

Co-Founder / Huck Endowed Chair Professor

Tandem Repeat / Pennsylvania State University

The production of the new product involved biofermentation to generate protein pulp, which was subsequently transformed into fibre. It’s essential for these processes to be integrated and operate simultaneously. However, this has been difficult domestically due to the decline of the American textile industry. Past efforts to manufacture bioengineered fibres in the United States fell short because they struggled with the spinning stage and were unable to produce fibres at a competitive cost.

Tandem Repeat was initially developed because nature employs gene duplication to form complex proteins by repeating unique tandem blocks like collagen, keratin, elastin, silk, squid ring teeth, and others. Currently, it has adopted Procell, combining protein and lyocell using chemistry and biology; this new name represents proteins generated through biomass fermentation, which supports large-scale production of proteins.

Your website also says: "We will launch with a capsule collection created through collaboration between designers, technicians, and craftspeople focused solely on maximizing what makes Squitex special." In what stage is this capsule collection right now? Which are the apparel segments that you are looking at?
Melik Demirel: We promote it worldwide using an experimental direct-to-consumer strategy business: www.sonachic.com

Knitting with sustainable fibres like Procell offers a unique opportunity to create eco-friendly textiles while promoting a more mindful approach to crafting. Procell fibre requires minimal water and no pesticides to cultivate, making it an attractive alternative to traditional fibres. When knitted, our protein based yarn creates a durable, breathable, and moisture-wicking fabric perfect for garments like sweaters, hats, and scarves. As the demand for sustainable textiles continues to grow, knitting with eco-friendly fibres like Procellreduces our environmental footprint and fosters a deeper connection between the maker, the material, and the planet.

Plus, generative AI is revolutionising the fashion industry by enabling the creation of innovative, customised, and sustainable designs. At Tandem Repeat, we utilise machine learning algorithms on fashion images to generate AI models, producing high-quality, photorealistic designs for our sweaters and cardigans. These models can also be fine-tuned to include specific design elements, such as patterns, colours, and fabrics, allowing designers to explore new ideas and iterate on existing designs quickly. Furthermore, generative AI can help reduce waste and promote sustainability in the fashion industry by generating designs that optimise fabric usage, minimise waste, and incorporate eco-friendly materials. As technology advances, generative AI is set to transform the fashion industry, enabling designers to create groundbreaking, bespoke designs that cater to the needs of a rapidly changing market.

Please tell us more about plant molecular farming. How does it work in the context of Squitex?
Melik Demirel: As mentioned earlier, we used corn, which is one of the common plants, as our organism of choice for producing protein powder. However, this is not economically feasible at this moment and requires more work to bring it to fruition.

What are the business plans like? Would you be manufacturing yourself? Or, would you be licensing others to do too? What does the financial future look like?
Melik Demirel: We just finished the feasibility of the protein factory for commercial fibre production. Last year, we secured $1.5 million from the federal government (Defense Industrial Manufacturing Consortium) to assess the engineering feasibility of the factory. This involves life cycle analysis, technoeconomics, basic engineering design and feasibility, volume sensitivity, FEL 1&2, market analysis, factory layouts, supply chain, and more. The next phase is the building phase, which will require $100 million, and we are currently awaiting funding from the government or private investors for this exciting venture.

Professor Melik Demirel is a scientist and innovator with expertise in biotechnology, nanotechnology and materials science. He received his PhD from Carnegie Mellon University (2002) and then worked at the Los Alamos National Laboratory (2003) and Max Planck Institute for Biophysical Chemistry as a von Humboldt fellow (2004). Highly respected in his field and recognised for his achievements, including being a senior National Academy of Inventors member and co-founding Tandem Repeat Technologies, Inc, he has received numerous international awards for his innovation in biomanufacturing. As the director of the CRAFT Center at Penn State, his contributions have been published in high-impact articles and patents and multiple cover pages for referenced journals. Additionally, he has educated over 50 eager students to make a difference in the world.