A natural material that looks and feels like real leather is taking the fashion world by storm. Scientists view mycelium—the vegetative part of a mushroom-producing fungus—as a planet-friendly alternative to animal hides and plastics.
Products crafted from this vegan leather are emerging, with others poised to hit the market soon. Among them are the Hermès Victoria bag, Lululemon's yoga accessories, Adidas' Stan Smith Mylo sneaker, and a Stella McCartney apparel collection.
The Adidas' Stan Smith Mylo concept sneaker, made in partnership with Bolt Threads, uses an alternative leather grown from mycelium; a commercial version is expected in the near future.
Hermès has held presales on the new bag, says Philip Ross, co-founder and chief technology officer of MycoWorks, a San Francisco Bay area firm whose materials constituted the design. By year-end, Ross expects several more clients to debut mycelium-based merchandise. With "comparable qualities to luxury leather," mycelium can be molded to engineer "all the different verticals within fashion," he says, particularly footwear and accessories.
More than a half-dozen trailblazers are fine-tuning mycelium to create next-generation leather materials, according to the Material Innovation Initiative, a nonprofit advocating for animal-free materials in the fashion, automotive, and home-goods industries. These high-performance products can supersede items derived from leather, silk, down, fur, wool, and exotic skins, says A. Sydney Gladman, the institute's chief scientific officer.
That's only the beginning of mycelium's untapped prowess. "We expect to see an uptick in commercial leather alternative applications for mycelium-based materials as companies refine their R&D [research and development] and scale up," Gladman says, adding that "technological innovation and untapped natural materials have the potential to transform the materials industry and solve the enormous environmental challenges it faces."
In fewer than 10 days in indoor agricultural farms, "we grow large slabs of mycelium that are many feet wide and long. We are not confined to the shape or geometry of an animal."
Reducing our carbon footprint becomes possible because mycelium can flourish in indoor farms, using agricultural waste as feedstock and emitting inherently low greenhouse gas emissions. Carbon dioxide is the primary greenhouse gas. "We often think that when plant tissues like wood rot, that they go from something to nothing," says Jonathan Schilling, professor of plant and microbial biology at the University of Minnesota and a member of MycoWorks' Scientific Advisory Board.
But that assumption doesn't hold true for all carbon in plant tissues. When the fungi dominating the decomposition of plants fulfill their function, they transform a large portion of carbon into fungal biomass, Schilling says. That, in turn, ends up in the soil, with mycelium forming a network underneath that traps the carbon.
Unlike the large amounts of fossil fuels needed to produce styrofoam, leather and plastic, less fuel-intensive processing is involved in creating similar materials with a fungal organism. While some fungi consist of a single cell, others are multicellular and develop as very fine threadlike structures. A mass of them collectively forms a "mycelium" that can be either loose and low density or tightly packed and high density. "When these fungi grow at extremely high density," Schilling explains, "they can take on the feel of a solid material such as styrofoam, leather or even plastic."
Tunable and supple in the cultivation process, mycelium is also reliably sturdy in composition. "We believe that mycelium has some unique attributes that differentiate it from plastic-based and animal-derived products," says Gavin McIntyre, who co-founded Ecovative Design, an upstate New York-based biomaterials company, in 2007 with the goal of displacing some environmentally burdensome materials and making "a meaningful impact on our planet."
After inventing a type of mushroom-based packaging for all sorts of goods, in 2013 the firm ventured into manufacturing mycelium that can be adapted for textiles, he says, because mushrooms are "nature's recycling system."
The company aims for its material—which is "so tough and tenacious" that it doesn't require any plastic add-on as reinforcement—to be generally accessible from a pricing standpoint and not confined to a luxury space. The cost, McIntyre says, would approach that of bovine leather, not the more upscale varieties of lamb and goat skins.
Already, production has taken off by leaps and bounds. In fewer than 10 days in indoor agricultural farms, "we grow large slabs of mycelium that are many feet wide and long," he says. "We are not confined to the shape or geometry of an animal," so there's a much lower scrap rate.
Decreasing the scrap rate is a major selling point. "Our customers can order the pieces to the way that they want them, and there is almost no waste in the processing," explains Ross of MycoWorks. "We can make ours thinner or thicker," depending on a client's specific needs. Growing materials locally also results in a reduction in transportation, shipping, and other supply chain costs, he says.
Yet another advantage to making things out of mycelium is its biodegradability at the end of an item's lifecycle. When a pair of old sneakers lands in a compost pile or landfill, it decomposes thanks to microbial processes that, once again, involve fungi. "It is cool to think that the same organism used to create a product can also be what recycles it, perhaps building something else useful in the same act," says biologist Schilling. That amounts to "more than a nice business model—it is a window into how sustainability works in nature."
A product can be called "sustainable" if it's biodegradable, leaves a minimal carbon footprint during production, and is also profitable, says Preeti Arya, an assistant professor at the Fashion Institute of Technology in New York City and faculty adviser to a student club of the American Association of Textile Chemists and Colorists.
On the opposite end of the spectrum, products composed of petroleum-based polymers don't biodegrade—they break down into smaller pieces or even particles. These remnants pollute landfills, oceans, and rivers, contaminating edible fish and eventually contributing to the growth of benign and cancerous tumors in humans, Arya says.
Commending the steps a few designers have taken toward bringing more environmentally conscious merchandise to consumers, she says, "I'm glad that they took the initiative because others also will try to be part of this competition toward sustainability." And consumers will take notice. "The more people become aware, the more these brands will start acting on it."
A further shift toward mycelium-based products has the capability to reap tremendous environmental dividends, says Drew Endy, associate chair of bioengineering at Stanford University and president of the BioBricks Foundation, which focuses on biotechnology in the public interest.
The continued development of "leather surrogates on a scaled and sustainable basis will provide the greatest benefit to the greatest number of people, in perpetuity," Endy says. "Transitioning the production of leather goods from a process that involves the industrial-scale slaughter of vertebrate mammals to a process that instead uses renewable fungal-based manufacturing will be more just."
At age 52, Glen Rouse suffered from arm weakness and a lot of muscle twitches. “I first thought something was wrong when I could not throw a 50-pound bag of dog food over the tailgate of my truck—something I use to do effortlessly,” said the 54-year-old resident of Anderson, California, about three hours north of San Francisco.
In August, Rouse retired as a forester for a private timber company, a job he had held for 31 years. The impetus: amyotrophic lateral sclerosis, or ALS, a progressive neuromuscular disease that is commonly known as Lou Gehrig’s disease, named after the New York Yankees’ first baseman who succumbed to it less than a month shy of his 40th birthday in 1941. ALS eventually robs an individual of the ability to talk, walk, chew, swallow and breathe.
Rouse is now dependent on ventilation through a nasal mask and uses a powerchair to get around. “I can no longer walk or use my arms very well,” he said. “I can still move my wrists and fingers. I can also transfer from my chair to the toilet if I have two of my friends help me.”
It’s “shocking” that modern medicine has very little to offer to people with this devastating condition, Rouse said. But there is hope on the horizon. Yesterday, the U.S. Food and Drug Administration approved Relyvrio, a drug made up of two parts, sodium phenylbutyrate and taurursodiol, to treat patients with ALS.
“This approval provides another important treatment option for ALS, a life-threatening disease that currently has no cure,” said Billy Dunn, director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, in a statement. “The FDA remains committed to facilitating the development of additional ALS treatments.”
Until this point, the FDA had approved only two other medications—Riluzole (rilutek) in 1995 and Radicava (edaravone) in 2017—to extend life in patients with ALS, which typically kills within two to five years after diagnosis. That’s why earlier this week, Rouse was optimistic about the FDA’s likely approval of a controversial new drug for ALS.
When Relyvrio is taken in addition to Riluzole, it appears to slow functional decline by an additional 25 percent and extend life by another 6 to 10 months, said Richard Bedlak, director of the Duke ALS Clinic. “It is not a cure, but it is definitely a step forward.”
“The whole ALS community is extremely excited about it,” he said the day before Relyvrio’s expected approval. “We are very hopeful. We’re on pins and needles.”
A study of 137 ALS patients did not result in “substantial evidence” that Relyvrio was effective, the agency’s Peripheral and Central Nervous System Drugs Advisory Committee concluded in March. However, after some persuasion from FDA officials, patients and their families, the committee met again and decided to recommend approving the drug.
In January 2019, following an ALS diagnosis in October the previous year, Jeff Sarnacki, of Chester, Maryland, was accepted into a trial for Relyvrio. “Because of the trial, we did experience hope and a greater sense of help than had we not had that opportunity,” said Juliet Taylor, his wife and caregiver. They both believed the drug “worked for him in giving him more time.”
In June 2019, Sarnacki chose an open-label extension, offered to patients by drug researchers after a study ends, and took the active drug until he died peacefully at home under hospice care in May 2020, five days after his 60th birthday. A retired agent with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives who later worked as a security consultant, Sarnacki lived about 19 months after diagnosis, which is shorter than the typical prognosis.
His symptoms had begun with leg cramps and foot drop in late fall 2017. At the end of life, he could only move a few fingers on his left hand and could not speak or eat by mouth; a feeding tube became necessary, Taylor said. He also took Radicava and Riluzole, the two previously approved drugs, for his ALS. “We were both incredulous that, so many years after Lou Gehrig’s own diagnosis, there were so few treatments available,” she said.
The dearth of successful treatments for ALS is “certainly not for lack of trying,” said Karen Raley Steffens, a registered nurse and ALS support services coordinator at the Les Turner ALS Foundation in Skokie, Ill. “There are thousands of researchers and scientists all over the world working tirelessly to try to develop treatments for ALS.”
Unfortunately, she adds, research takes time and exorbitant amounts of funding, while bureaucratic challenges persist. The rare disease also manifests and progresses in many different ways, so many treatments are needed.
As of 2017, the Centers for Disease Control and Prevention estimated that more than 31,000 people in the U.S. live with ALS, and an average of 5,000 people are newly diagnosed every year.
Most cases of ALS are sporadic, meaning that doctors don’t know the cause. There is about a one-year interval between symptom onset and an ALS diagnosis for most patients, so many motor neurons are lost by the time individuals can enroll in a clinical trial, said Richard Bedlack, professor of neurology and director of the Duke ALS Clinic in Durham, North Carolina.
Bedlack found the new drug, Relyvrio, to be “very promising,” which is why he testified to the FDA in favor of approval. (He’s a consultant and disease state speaker for multiple companies including Amylyx, manufacturer of Relyvrio.)
The “drug has different mechanisms of action than the currently approved treatments,” said Bedlack, who is also chief of neurology at the Durham Veterans Affairs Medical Center. He adds that, when Relyvrio is taken in addition to Riluzole, it appears to slow functional decline by an additional 25 percent and extend life by another 6 to 10 months. “It is not a cure, but it is definitely a step forward.”
T. Scott Diesing, a neurohospitalist and director of general neurology at the University of Nebraska Medical Center in Omaha, said he hopes the drug is “as good as people anticipated it should be, because there are not too many options for these patients.”
So far, Rouse's voice is holding up, but he knows the day will come when ALS will steal that and much more from him.
ALS is 100 percent fatal, with some patients dying as soon as a year after diagnosis. A few have lasted as long as 15 years, but those are the exceptions, Diesing said.
“If this drug can provide even months of additional life, or would maintain quality of life, that’s a big deal,” he notes, adding that “the patients are saying, ‘I know it’s not proven conclusively, but what do we have to lose?’ So, they would like to try it while additional studies are ongoing.” The drug has already been approved in Canada.
As his disease progresses, Rouse hopes to get a speech-to-text voice-generating computer that he can control with his eyes. So far, his voice is holding up, but he knows the day will come when ALS will steal that and much more from him. He works at I AM ALS, a patient-led community, and six of his friends have already died of the disease.
“Every time I lose a friend to ALS, I grieve and am sad but I resolve myself to keep working harder for them, myself and others,” Rouse said. “People living with ALS find great purpose in life advocating and trying to make a difference.”
The Friday Five covers important stories in health and science research that you may have missed - usually over the previous week, but today's episode is a lookback on important studies over the month of September.
Most recently, on September 27, pharmaceuticals Biogen and Eisai announced that a clinical trial showed their drug, lecanemab, can slow the rate of Alzheimer's disease. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend and the new month.
This Friday Five episode covers the following studies published and announced over the past month:
- A new drug is shown to slow the rate of Alzheimer's disease
- The need for speed if you want to reduce your risk of dementia
- How to refreeze the north and south poles
- Ancient wisdom about Neti pots could pay off for Covid
- Two women, one man and a baby