Nature's Engineers - Part 7: Growing Products

The Spider’s Miracle

Every morning, millions of garden spiders perform a manufacturing miracle.

Using nothing but water, protein, and their own body chemistry, they produce silk that is:

• Stronger than steel — Five times stronger per unit weight

• Tougher than Kevlar — Able to stretch 30% before breaking

• Completely biodegradable — Decomposes naturally when discarded

• Produced at room temperature — No furnaces, no pressure, no toxic solvents

If an engineer proposed such a material, they’d be laughed out of the room. It sounds impossible. Yet spiders have been doing it for 400 million years.

Compare this to how humans make high-performance fibers:

Kevlar production:

1. Start with petroleum (extracted from underground reservoirs)

2. Convert to para-phenylenediamine and terephthaloyl chloride (toxic chemicals)

3. React in concentrated sulfuric acid (extremely hazardous)

4. Spin at high temperature and pressure

5. Wash and treat with additional chemicals

Spider silk production:

1. Spider eats flies

2. Silk comes out

The spider’s process is so efficient it makes our most advanced manufacturing look primitive.

Why We Can’t Just Farm Spiders

The obvious question: why not just collect spider silk like we collect silkworm silk?

The answer is spider behavior. Silkworms are caterpillars—passive, crowdable, and docile. You can raise thousands in a small space.

Spiders are predators. Put two in the same cage, and one eats the other. Large-scale spider farming is impossible.

Some researchers have tried “milking” individual spiders—restraining them and drawing silk from their spinnerets. It works, but it’s incredibly slow. A single spider produces only a few meters of silk per milking session.

In 2009, a team created a golden cape from the silk of over one million golden orb spiders, collected over four years. The cape is beautiful—but hardly a scalable manufacturing process.

The solution would have to come from a different direction: instead of farming spiders, we would learn to make silk without them.

Decoding the Recipe

Spider silk is a protein—a long chain of amino acids folded into a specific shape. The strength comes from the folding pattern: regions of crystalline beta-sheets (very rigid) alternating with amorphous regions (stretchy).

In the 1990s, researchers sequenced spider silk genes, discovering the DNA instructions that spiders use to manufacture silk proteins. The genes were longer and more repetitive than expected—challenging to work with using standard genetic engineering techniques.

The next step was to transplant these genes into other organisms—bacteria, yeast, plants, goats—that could be farmed conventionally. Make these organisms produce silk protein, then spin it into fiber.

This proved extraordinarily difficult.

The Production Problem

Bacteria and yeast could be engineered to produce silk proteins, but only in small amounts. The cells often died or became unstable. The proteins clogged cellular machinery.

The Spinning Problem

Even when proteins were produced, converting them into fiber was challenging. In a spider, proteins are stored as a liquid and transformed into solid fiber by a precisely controlled spinning process involving:

• pH changes along the spinning duct

• Ion exchange (potassium replaces sodium)

• Physical shearing and drawing

• Controlled dehydration

Replicating this process artificially required years of research.

The Breakthroughs

By the 2010s, several companies had made significant progress:

Bolt Threads — Using engineered yeast to produce silk proteins in fermentation tanks (similar to brewing beer), then spinning into fiber branded Microsilk. The company has partnered with major fashion brands for prototype products.

Spiber — A Japanese company that achieved commercial-scale production using engineered bacteria. Their Brewed Protein fiber is now used in outdoor apparel.

AMSilk — A German company producing spider silk proteins for cosmetics, medical devices, and coatings.

None have achieved the strength of natural spider silk yet—but they’re getting closer.

Mycelium: The Underground Network

While spider silk replicates a product nature already makes, mycelium materials take a different approach: using fungal growth as a manufacturing process.

Mycelium is the vegetative part of a fungus—a network of microscopic threads (hyphae) that spread through soil, wood, or other substrates. What we call a “mushroom” is just the fruiting body; the mycelium is the main organism, often covering enormous areas underground.

From Waste to Material

The insight was simple: mycelium will grow on almost any organic material, binding it together into a solid mass. Feed it agricultural waste—corn stalks, sawdust, cotton husks—and it will consume the cellulose while weaving its threads throughout.

Stop the growth at the right moment, kill the fungus with heat, and you have a composite material: organic particles bound by a matrix of fungal fibers.

Ecovative Design, founded in 2007, pioneered this approach. Their process:

1. Mix agricultural waste with mycelium spawn

2. Pack into molds of desired shape

3. Let grow for 4-7 days in darkness

4. Heat-treat to stop growth and kill fungus

5. Remove finished product from mold

The result is a lightweight, strong, flame-resistant, insulating material that’s completely biodegradable. Throw it in the garden, and it composts in weeks.

Applications

Packaging — Mycelium packaging can replace polystyrene foam for shipping electronics, wine bottles, and fragile goods. IKEA and Dell have adopted it for selected products.

Insulation — Mycelium panels provide thermal and acoustic insulation for buildings. They’re naturally fire-resistant (the fungus won’t burn easily) and non-toxic.

Leather alternatives — Companies like Bolt Threads (again) and MycoWorks are producing mycelium-based leather substitutes. The material can be grown to any shape, dyed, and finished like animal leather.

Building materials — Experimental projects have used mycelium composites for bricks, panels, and even load-bearing structures. A “growing” building that constructs itself from waste is theoretically possible.

The Carbon Equation

The math on mycelium materials is remarkable:

• Feedstock: Agricultural waste (carbon already captured from atmosphere)

• Energy: Minimal (fungus grows at room temperature)

• Waste: None (everything becomes product or compost)

• End of life: Complete biodegradation (carbon returns to soil)

Compare to polystyrene foam:

• Feedstock: Petroleum (adding ancient carbon to atmosphere)

• Energy: High (chemical processing at elevated temperatures)

• Waste: Significant (manufacturing byproducts)

• End of life: Hundreds of years in landfill

Mycelium packaging isn’t just competitive—it’s carbon negative. Each kilogram of mycelium packaging represents carbon pulled from the atmosphere and stored (temporarily) in useful form.

Bacterial Cellulose: Growing Fabric

Suzanne Lee was a fashion designer frustrated with traditional textile production. The fashion industry is one of the world’s worst polluters—cotton farming consumes vast water and pesticides; synthetic fibers are derived from petroleum; dyeing and finishing contaminate waterways.

Lee wondered: could fabric be grown instead of manufactured?

Her answer came from an unlikely source: kombucha.

The SCOBY

Kombucha is a fermented tea drink produced using a SCOBY (Symbiotic Culture of Bacteria and Yeast). The SCOBY floats on the surface of sweetened tea, feeding on sugar and producing acids that give kombucha its distinctive taste.

But the SCOBY also produces something else: bacterial cellulose—a mat of pure cellulose fibers that forms at the liquid surface.

This cellulose is chemically identical to plant cellulose (the material in cotton) but produced by bacteria rather than plants. It grows as a continuous sheet that can be harvested, dried, and processed.

Biocouture

Lee founded Biocouture in 2004 to explore bacterial cellulose as a textile. The process:

1. Prepare sweet green tea in shallow trays

2. Inoculate with cellulose-producing bacteria

3. Wait 2-3 weeks as bacterial mat grows on surface

4. Harvest, wash, and dry the cellulose sheet

5. Treat and finish as desired

The resulting material looks and feels like leather or paper, depending on thickness and treatment. It can be dyed, molded, and stitched like conventional fabrics.

Lee produced prototype jackets, shoes, and accessories entirely from grown bacterial cellulose. The materials are fully biodegradable—a bacterial cellulose jacket, composted at end of life, becomes soil nutrients.

Modern Developments

The concept has matured significantly:

Modern Meadow — Produces “bioleather” from lab-grown collagen (the protein in animal leather), created by engineered yeast. The material is chemically identical to leather but requires no animal farming.

Bolt Threads (again!) — Their Mylo material combines mycelium technology with finishing processes to create a leather alternative used by Adidas, Stella McCartney, and Lululemon.

Orange Fiber — Uses cellulose extracted from citrus juice waste to produce sustainable textiles.

Photosynthesis: Nature’s Battery

The ultimate biofabrication challenge is energy itself.

Plants capture sunlight and convert it to chemical energy through photosynthesis. Every living thing ultimately runs on this process—either directly (plants) or indirectly (animals eating plants, or eating animals that eat plants).

Artificial photosynthesis—devices that capture sunlight and store it as fuel—has been a research goal for decades. Some approaches are purely synthetic; others incorporate biological components.

Bio-batteries use living organisms or their components to generate electricity:

• Microbial fuel cells — Bacteria that naturally produce electrons as part of their metabolism, captured via electrodes

• Photosynthetic panels — Living algae or cyanobacteria that generate current when exposed to light

• Enzyme batteries — Isolated biological enzymes that catalyze electrochemical reactions

None of these yet compete with conventional batteries on performance or cost. But they offer unique advantages:

• Self-repair — Living systems can repair damage automatically

• Self-replication — Given nutrients, living systems grow and reproduce

• Sustainability — No rare earth metals or toxic chemicals required

The Paradigm Shift

Traditional manufacturing follows a pattern:

1. Extract raw materials from the earth

2. Heat them to extreme temperatures

3. Force them into desired shapes

4. Treat with chemicals to achieve properties

5. Discard when finished (often into landfills or oceans)

Biofabrication inverts this:

1. Grow materials using living organisms

2. Feed with agricultural or industrial waste

3. Shape during growth (in molds or scaffolds)

4. Finish with minimal processing

5. Compost at end of life

The energy difference is staggering. Manufacturing steel requires 25-35 gigajoules per ton. Growing mycelium requires less than 1 gigajoule per ton.

The waste difference is equally dramatic. Manufacturing typically converts 4-10% of input materials into products; the rest becomes waste. Biofabrication can approach 100% conversion—organisms are efficient by evolutionary necessity.

What’s Missing?

Biofabrication sounds like a panacea. Why isn’t it already dominant?

Scale — Most biofabrication processes are still small-scale. Growing enough mycelium to replace global polystyrene production would require vast facilities and feedstock logistics.

Speed — Biology is slow. Growing mycelium takes days; injection molding takes seconds. For high-volume products, the cycle time disadvantage is significant.

Consistency — Living organisms are variable. A batch of bacteria may produce different proteins than the last batch. Achieving industrial-quality consistency requires sophisticated process control.

Properties — For many applications, synthetic materials still outperform biological alternatives. Spider silk companies have yet to match natural spider silk, let alone exceed it.

Infrastructure — The world’s manufacturing infrastructure is built around extraction and heating. Switching to biofabrication requires entirely new supply chains, equipment, and expertise.

The Transition

Despite these challenges, biofabricated products are reaching markets:

• Bolt Threads’ Microsilk in luxury garments

• Ecovative’s mycelium packaging at IKEA and Dell

• Modern Meadow’s bioleather in consumer products

• Spiber’s Brewed Protein in outdoor apparel

Each commercial success validates the approach and attracts investment for further development.

The trajectory follows the pattern of previous technological transitions:

1. Laboratory curiosity — Researchers demonstrate possibility

2. Expensive niche products — Early commercial applications at premium prices

3. Scaling and cost reduction — Process improvements and economies of scale

4. Mass market adoption — Biofabricated materials become default choice

We’re somewhere between stages 2 and 3. The laboratory curiosity phase is largely complete. Commercial products exist but remain expensive. The challenge now is scaling.

The Vision

Imagine a factory of the future:

• Vats of engineered microorganisms producing silk proteins from sugar

• Mycelium growing rooms transforming agricultural waste into packaging

• Bacterial cellulose farms harvesting continuous sheets of fabric

• All powered by renewable energy, producing zero waste

This isn’t science fiction. Every component exists today, proven at least at pilot scale. The engineering challenges are substantial but not fundamental.

Nature has been manufacturing materials this way for billions of years. We’re finally learning to do the same.

References

• Holland, C. et al. “The Biomedical Use of Silk: Past, Present, Future.” Advanced Healthcare Materials, 2019.

• Jones, M. et al. “Leather-Like Material from Fungi: A Review.” Trends in Biotechnology, 2020.

• Lee, S. “Biocouture: Growing Clothes from Bacteria.” TEDx, 2011.

• Kapsali, V. Biomimicry for Designers. Thames & Hudson, 2016.

• Bayer, E. “The Mycelium Revolution Is Upon Us.” Scientific American, 2019.

Next in the series: Swarms and Soft Robots — Where biomimicry is heading: collective intelligence, morphing machines, and self-assembling systems.