Tandem Repeat founder tells Sportstextiles Procell fibre is ready to scale
In an interview with Sportstextiles.com, Professor Melik Demirel, founder of US biotech start-up Tandem Repeat, said the company’s yeast-brewed protein fibre Procell is moving rapidly towards commercial scale and could undercut both wool and cotton.
Procell is made through biomass fermentation, using yeast that consumes brewing and pharmaceutical waste. “This makes our raw material nearly free,” Prof Demirel explained, adding that the fibre already shows twice the strength of wool at half the price.
Founded in 2020 out of Penn State University, Tandem Repeat has produced 500kg of Procell at pilot scale and aims for 10 tonnes in 2025 and 300 tonnes in 2026 with a European lyocell partner. To test the market, it launched a short run of Sonachic sweaters earlier this year. Other projects include thermal insulation padding for military use and continued research into squid-inspired Squitex fibres, which offer self-healing and thermoregulating properties.
Tandem Repeat has filed more than 20 patents and secured $2 million in venture capital and $6.8 million in grants, including $1.5 million from the US Climate Positive programme to prepare a factory proposal in North Carolina.
Speaking to Sportstextiles.com, Prof Demirel said Procell could play a role in filling the gap left by shrinking wool supply: “I am not looking to take wool’s market share but to retrieve the 1 million tonnes it has lost.”
