A Promising Path to Sustainable Green Chemistry: Nature as model, measure, and mentor
December 16, 2010
This essay is in response to: How can innovations in technology and research reduce exposures to toxic chemicals?
Nature is alive with chemistry. Many Americans would be surprised to learn that the natural world is replete with chemistry and chemicals. It goes against their assumption that chemicals are a man-made blight on an otherwise chemical-free natural world. Nothing could be further from the truth. Nature is the ultimate chemist and chemical engineer and she's been practicing and perfecting her craft since life first appeared on plant Earth. One of her first technological triumphs—photosynthesizing complex carbon-based compounds at ambient conditions using carbon dioxide as the carbon source—is a multi-billion year old technology. It turns out sustainability and green chemistry are not just modern-day ideas.
Long before we started talking about preserving healthy habitats, life figured out that better living is indeed possible through chemistry (e.g., adhesives that bind to dirty, rough, wet surfaces; vibrant colors born of structure rather than pigment; strong, flexible, lightweight, biodegradable fibers; super hard ceramics that resist cracking) and that chemistry is indeed possible through life-friendly means (e.g., using locally available non-toxic materials; freely available energy sources; catalytic transformations; chemical-specific reactions at ambient conditions; cyclic processes).
The time is ripe for biomimicry to significantly contribute to green chemistry. As we enter the second decade of the 21st Century, science is advancing on two important fronts: the high resolution with which we can peer into the molecular mechanisms of the natural world, and the controlled dexterity with which we can manipulate at the molecular level. Biomimicry—the art and science of learning from the natural world rather than extracting from it—taps into Nature's chemical prowess as a source of inspiration for a sustainable chemical industry sector. Some well-known biomimicry success stories include PureBond wood adhesive that took cues from the sea mussel clinging tenaciously to rocks; Lotusan paints that took cues from the self-cleaning Lotus leaf; Calera cement that took cues from rock-building coral reefs; and Novomer catalysts that took cues from photosynthetic enzymes.
Nature and industry have more in common than meets the eye. While it might seem that Nature and industry are diametrically opposed, they're really two sides of the same coin. Both industry and Nature harness energy and use that energy in a controlled way to build complex systems. Industry burns fossil fuel to generate steam to turn turbines to generate a controlled flow of electrons that power the refining of crude oil into ethylene that serves as the building block for myriad complex carbon-based synthetics such as fibers, pharmaceuticals, and plastics. On the other side of the coin, Nature captures the energy of incoming photons to trigger a controlled flow of electrons that power cellular machinery that use carbon dioxide as the building block for myriad complex carbon-based materials such as natural fibers, medicinal compounds, and polymers.
The major difference is that Nature has learned to do it while creating conditions conducive to life: water-based processes leverage molecular self-assembly at ambient temperatures and pressures. Despite impressive new technologies, industry still largely depends on petrochemical solvent-based processes that require heat, beat, and treat methodologies.
Yes, Nature produces and uses toxic chemicals, but the primary function of Nature's toxins is intended toxicity for protection, reproduction, or predation functions. In contrast, the toxicity of man-made chemicals is often an unintended feature of compounds synthesized for other functions such as adhesion, structural support, fragrance, color, etc.
Can Nature provide the answer to all public and environmental health challenges facing modern chemical technologies? Maybe not. Could Nature be a rich source of innovative new ideas that could dramatically transform modern chemical technologies into ones that perform better and tread softly on the Earth? Seems like a winning bet, particularly for forward-thinking businesses and governments.
What steps can government take now? Work with leaders in the chemical industry, research universities, and the public interest community to identify the top chemicals challenges facing our nation and the world (similar to the list of target research areas developed by the American Chemical Society's Green Chemistry Institute and the Pharmaceutical Roundtable). Allocate resources to investigate the strategies Nature uses to solve the same challenges and develop potential solutions based on the deep patterns that emerge from such research. At stages along the iterative process of developing biomimetic solutions, test the performance of the new technology by comparing it to the set of life's principles that the inspiring natural strategies adhere to (e.g., water-based, non-toxic, biodegradable).
In the meantime, everyone should take a moment to go out into Nature and when you look at sunbathing leaves, web-weaving spiders, preening ducks, colorful butterflies, medicinal herbs, or fragrant flowers, take a moment to think about the sophisticated, elegant, quiet chemistry going on behind the scenes.