I can’t hide from the oncoming leather revolution
By S Ramadorai, Raman Srinivasan and S Shivaramakrishna
India is home to the largest cattle population – over 300 million, including 110 million water buffaloes. This large herd is not only a source of livelihood, but also means wealth and well-being for our 100 million marginal dairy farmers. We are also the world’s largest beef exporter. In addition, our large herd makes India a leader in the global leather industry.
But as with meat and milk, consumer preferences and industry trends are changing rapidly. Influential fashion brands have woken up to ethical alternatives to leather and fur. Other factors are also forcing change. Last November, Denmark slaughtered 17 million mink because of Covid-19. Soon after, Kopenhagen Fur, the main hub for the mink and other fur trade, announced it would shut down by 2023. More recently, Israel became the first country to ban the sale of fur. “Using skin and fur … is immoral … and inflicts unspeakable cruelty and suffering,” Israeli Minister of Environmental Protection Gila Gamliel said in a statement.
tannery of the world
However, we are proud to be the world’s tannery, producing 3 billion square feet of leather per year, enough to make three pairs of shoes for every Indian. In fact, we are the second largest producer of leather shoes and clothing. The leather industry employs more than 4.5 million people in dozens of industrial clusters across the country. Animal rights activists, public health experts and environmentalists have frequently pointed out the negative impact of tanneries on the environment and public health. In a typical process, a series of chemicals successively changes the original composition of the skin. For example, alkalis help to break down and remove non-fibrous proteins from the skin. Subsequently, the skin is “pickled” in sulfuric acid and other chemicals. Still later, chromium sulfate is used to tan the skin, followed by a second tanning with vegetable or synthetic tannins to soften the leather. Each step results in the discharge of effluents into the environment. In some clusters, the damage caused by such activities is visible on satellite imagery. As hideous as it may be, the journey from skin to leather is necessary to stabilize the living composite material in layers of skin as leather.
Skin in the game
Mammalian skins, like milk, are a natural wonder. The skin is obviously the largest organ of all mammals. Multifunctional by nature, it protects, detects and regulates. How did biology design this tactile interface? Fundamental scientific work to understand leather was carried out in Chennai in the early 1950s. GN Ramadchandran, then a young professor of physics at the University of Madras, decoded the structure of collagen, beating famous scientists like Watson and Crick in Cambridge, and Pauling et al at Caltech. Through diligent experiments on the tail tendon specially obtained from an Australian kangaroo and insightful mathematical modeling, Ramachandran showed that the structure of collagen is a triple helix and coiled. Not only that, he created a brilliant theoretical framework, the Ramachandran plot, for protein structures that is used around the world today.
Collagen, the major structural protein found in skin and connective tissue, is the most abundant protein (25-35%) in mammals. Long, intertwined collagen fibers, locally aligned with the shape of the mammal’s body, form the structural basis of the skin. For example, in the event of an injury, the unique biomechanical properties of the skin help speed wound closure and healing. Surgeons, especially plastic surgeons, are trained to take advantage of the unique properties of mammalian skin. Some 2,500 years ago, Charakka and Sushruta described the structure of the skin as a multi-layered composite with remarkable information about the functional properties of various layers. More than elective cosmetic surgery patients, severe burns have inspired attempts to grow human skin in the laboratory.
Do Druids Dream of Synbio Sheep?
The pioneers of regenerative medicine developed various methods and techniques to repair and replace tissues and even organs. However, technologies such as 3D printing of biological tissues are still far from mainstream. Making these revolutionary technologies affordable and sustainable is a challenge, requiring an interdisciplinary approach.
Professor Gabor Forgacs is the classic intellectual migrant. Trained as a theoretical physicist in Hungary, he became a biologist physicist and later became an entrepreneur in synthetic biology. While in the Biological Physics Group at the University of Missouri, he founded Organovo in 2007 with his son, Andras Forgacs. Organovo aimed to 3D print biological tissues and organs. Four years later, Forgacs’ father-son team founded another company, Modern Meadows, to grow leather using synthetic biology techniques.
Where does the leather go?
Following largely synthetic biology methods similar to making heme for meat or caseins for milk, entrepreneurs are now brewing collagen proteins. Once again, a familiar five step process is followed. First, the Forgacs team scientists sequenced or “read” the genomes of dozens of mammals. Then the specific genetic code for the production of collagen is identified. Then, the genetic instructions for the production of collagen are inserted into industrially exploited microbes. The fourth step is a precision fermentation process, much like brewing beer. Microbes with a collagen-producing code are grown under controlled conditions to produce collagen in scalable amounts. The fifth step gives the synbio leather.
Synbio leather production technology has turned out to be very attractive. In fact, some companies are successfully experimenting with more complex organisms like filamentous fungi as possible industry model organisms. A well-funded start-up, Bolt Threads, boldly set out to turn spider silk into profit, but then struggled to unravel issues of economic expansion. They produced spider silk proteins using engineered microbes, and then even spun and woven it into small amounts of ties and other fashion accessories. However, the initial promise of being able to ferment and spin silk fiber with superior engineered properties and an attractive economy has proven elusive. The yeast was not up to par, but there was room for the mushrooms. They tied their fortune to synbio leather.
Scientists at the start-up began exploring filamentous fungi to produce mycelial leather, dubbed Mylo. Early next year, yoga clothing brand Lululemon will likely launch mushroom-derived leather yoga mats and bags. Stella McCartney also launched mycelia leather clothing. And other big brands, like Adidas, are replacing animal leather in their shoes with leather made using synthetic biology. With our large leather industry, maybe we want to understand the coming disruption.
Ramadorai is the former vice president of TCS, Srinivasan is the head of TCS Ignite and Shivaramakrishna is a researcher at TCS