A fermentation byproduct might help to solve two major global challenges: world hunger and the environmental impact of fast fashion. The leftover yeast from brewing beer, wine or even to make some pharmaceuticals can be repurposed to produce high-performance fibers stronger than natural fibers with significantly less environmental impact, according to a new study led by researchers at Penn State and published today (Nov. 3) in the Proceedings of the National Academy of Sciences.
The yeast biomass - composed of proteins, fatty molecules called lipids and sugars - left over from alcohol and pharmaceutical production is regarded as waste, but lead author Melik Demirel, Pearce Professor of Engineering and Huck Chair in Biomimetic Materials at Penn State, said his team realized they could repurpose the material to make fibers using a previously developed process. The researchers successfully achieved pilot-scale production of the fiber - producing more than 1,000pounds - in a factory in Germany, with continuous and batch production for more than 100 hours per run of fiber spinning.
They also used data collected during this production for a lifecycle assessment, which assessed the needs and impact of the product from obtaining the raw fermentation byproduct through its life to disposal and its cost, and to evaluate the economic viability of the technology. The analysis predicted the cost, water use, production output, greenhouse gas emissions and more at every stage. Ultimately, the researchers found that the commercial-scale production of the fermentation-based fiber could compete with wool and other fibers at scale but with considerably fewer resources, including far less land - even when accounting for the land needed to grow the crops used in the fermentation processes that eventually produce the yeast biomass.
"Just as hunter-gatherers domesticated sheep for wool 11,000 years ago, we're domesticating yeast for a fiber that could shift the agricultural lens to focus far more resources to food crops," said Demirel, who is also affiliated with the Materials Research Institute and the Institute of Energy and the Environment, both at Penn State.
"We successfully demonstrated that this material can be made cheaply - for $6 or less per kilogram, which is about 2.2 pounds, compared to wool's $10 to $12 per kilogram - with significantly less water and land but improved performance compared to any other natural or processed fibers, while also nearly eliminating greenhouse gas emissions. The saved resources could be applied elsewhere, like repurposing land to grow food crops."
