Synthetic Biology

“Synthetic biology” (“synbio,” for short) is a field that redesigns living organisms (often microbes) by editing their DNA, so that they produce useful molecules or gain other abilities. Bacteria might be engineered to produce industrial chemicals or edible proteins, for instance, or to sense and indicate the presence a toxin, or to produce an enzyme that can decompose plastics. The field encompasses dozens of particular disciplines, from molecular biology to computer science to chemical engineering.

Some of the first practical tools for reading, writing, and editing DNA were developed in the early 2000s; and the discovery of CRISPR-cas9 in 2009 offered a technique for gene-editing that was faster and far more precise than anything that had come before. In the years since, the costs of computing power and lab automation have plummeted, and the costs of genome sequencing and DNA synthesis have done the same. The result is that the field is accelerating exponentially in scope and ability, with a growing library of tools that are ever more precise, faster, and cheaper. Today, synthetic biology is at a similar place to the internet in the early 1990s: people who are paying attention can see that something big and transformative is starting, and visionaries have ideas about directions it might go; but no one can foresee exactly what it will unlock, any more than someone using a dial-up modem to connect their personal computer to the internet could foresee what people now use their smartphones to do.

The range of climate problems that synthetic biology could help to solve is wide and varied – and it is sure to expand in coming years. Just to give you some ideas, here are some examples of ways researchers and startups are already working to deploy synbio in the service of the climate today.

Replacing plastics and other petrochemicals

We use fossil hydrocarbons like oil and gas not just for fuel, but as the feedstocks from which we make plastics and thousands of different chemicals. The process of refining oil and gas into plastics and other chemicals emits large amounts of greenhouse gas. (2.2% of global GHG emissions are non-energy “process emissions” from making chemicals, and another 3.6% of emissions are from burning fossil fuels for energy to power the chemical refining process.) The refining process also drives some of the worst environmental injustice, because it pollutes the air and water in poor and vulnerable communities near refineries with toxins and carcinogens.

Synthetic biology holds out the promise of making chemicals without using fossil fuels as feedstocks. Some startups, like Solugen, start from biological feedstocks (sugar, in Solugen’s case), and then use enzymes from genetically engineered microbes to turn it into useful chemicals. Others, like Genecis begin from organic waste material, and use engineered bacteria to turn it into plastic. Still others, like Rubi, start from pure carbon dioxide, which can be sourced from factory emissions by using carbon capture or from the atmosphere using direct air capture, and use engineered bacteria to turn it into textiles. And Lanzatech does something similar to turn captured carbon dioxide into ethanol, which can then be used to make jet fuel.

A common theme underlies all of these: living things are really good at taking carbon (usually from plants that have pulled it out of the air through photosynthesis), and then using it as the main ingredient to manufacture a near-infinite variety of organic molecules. You could almost say: that’s what living organisms do. It has not been in organisms’ interests before now to produce many of the particular carbon-based chemicals that humans find useful, and so we have made them ourselves by refining fossil hydrocarbons. But there’s no reason to think we can’t teach living organisms either to make all of these chemicals themselves, or to produce enzymes that will allow us to make them without the energy use, emissions and pollution of current methods.

Agriculture

The global population will grow from its current 8 billion to more than 10 billion people in the coming decades. At the same time, billions of people are expected to climb from poverty into the global middle class, and so will be able to afford the kind of meat-rich diet that people in wealthy countries currently enjoy. If current trends continue, this will mean that vast tracts of forest and other wildlands will be destroyed to make way for additional cropland and pasture; it will mean increasing nitrous oxide (a powerful greenhouse gas) and nitrogen runoff from fertilizer, and it will mean increasing methane (another powerful greenhouse gas) from cattle and other ruminants. All of these are problems that synthetic biology could help to solve.

To begin with the simplest and most obvious: synthetic biology offers a powerful set of tools with which to increase crop yields, so that we can grow more food on existing farmland, thus reducing pressure to convert forest and other wildlands to agricultural use. By the same token, synthetic biology can help to create crops that are more resilient to draughts, floods, and other forms of extreme weather that climate change will bring. 

Companies like Pivot Bio and Kula Bio are working to engineer microbes that can fix nitrogen from the air (that is, turn it into a form that plants can use), and so reduce or eliminate the need to apply synthetic nitrogen fertilizer and the nitrous oxide and nitrogen runoff it produces (as well as the large greenhouse gas emissions currently required to produce it). (Companies like Boost Biomes are also working to engineer microbes that will work as biofungicides and biopesticides, avoiding the need for toxic chemical fungicides and pesticides.)

And a huge range of companies are deploying synthetic biology to produce alternative proteins, so that we can farm fewer animals. A modest example: Impossible Foods used synthetic biology to make yeast produce heme, a molecule normally found in animals, so that Impossible Burgers taste more like animal meat. Dozens or hundreds of startups are seeking to go much further, using synthetic biology to produce alternatives to animal protein. Zero Cow Factory already uses engineered microbes to produce the same casein protein that comes from cows’ milk. If companies succeed in making alternatives that taste just as good or better than animal meat and cost less, it would be game-changing for the planet. 

Other applications

These are just the most obvious applications. Some startups are working to engineers microbes and plants that can “bio-mine” minerals and metals from the earth with far less environmental destruction than traditional mining. Others are making enzymes that can break down plastics in the environment. Still others are making trees that can grow and suck carbon from the atmosphere quickly, and then resist decomposition and so sequester the carbon in their biomass for centuries. 

These examples are just the beginning. Living organisms are incredible, self-replicating chemical machines, more complex than any machine humans have ever made, and with astonishing powers to build and rearrange the molecules that make up the physical world. Our growing ability to re-engineer these machines for our own purposes may usher in a revolution as transformative as the industrial revolution, helping us to undo some of the damage to our climate that the industrial revolution unleashed.

The three podcasts below interview the founders of three, different synbio startups. We found each of these both illuminating and inspiring: they give you some sense of where the discipline might go, and how it might get there.

Also check out Homeworld Collective, a nonprofit working to foster the emerging climate biotech community, provide thought leadership, and catalyze action.