From aeroplanes made of silk to microbes engineered to eat chemical pollutants, the synthetic biology revolution is moving from the lab to the real world.
In its simplest definition, synthetic biology changes DNA's instructions to make cells produce specific substances, or acquire new abilities, such as cleaning up pollutants. The instruction set is synthetic (written chemically) but to cells, it seems natural. The cells themselves are not modified but are used to produce different substances. The two components at the core of the process are synthetic DNA and the cell type/strain. Achieving a desired outcome rests on an optimum combination of the two.
Mapping the human genome in the early 2000s was a major turning point for the discipline.
“What lay behind that was the ability to sequence DNA accurately and write synthetic DNA, which we can now do effectively, quickly and at low cost,” says Richard Kitney, Professor of biomedical systems engineering at Imperial College London.
The revolution now bearing fruit is also the product of a mindset shift, according to Dan Widmaier, CEO and founder of Bolt Threads, an alternative materials fashion startup. “The big advent,” he explains, “was moving from trying to observe and understand the mechanisms of biology, and instead looking at biology like an engineer would look at a machine and trying to use its functionality to do something else.”
Today, synthetic biology may be most impactful for tackling the environmental crisis by providing entirely new ways to make materials, fuels and food. The fashion industry, for instance, generates about 1-1.5 per cent of global GDP but at a heavy environmental cost. High rates of product incineration and landfill disposal mean that the industry represents about 10 per cent of global emissions, according to the World Bank; at the same time, millions of tons of microfibres from production are finding their way into oceans, where they can enter the food chain.
The company Bolt Threads uses synthetic biology to develop sustainable fabrics. Companies—including Kering, lululemon and Adidas—have invested to secure exclusive access. One product, called Mylo, uses mycelium, the fungus that fruits mushrooms (same as a tree fruits an apple), coaxing it into other structures, such as clothing fibres, by controlling temperature, CO2 and airflow.
“There’s one perfect example of a working materials economy that is perfectly circular, and that's the 4bn-year lifespan of earth and the biosphere,” says Widmaier. “Life has evolved fantastic mechanisms for recycling pretty much anything.” He cites as an example spider’s silk, a natural super-material that is, relative to weight, between five and ten times the tensile strength of steel.
Bolt Threads is developing proteins inspired by spider’s silk, applying bioengineering techniques to put genes into yeast and produce the protein in larger quantities through fermentation. The resulting silk protein is then purified and spun into fibres used in fabrics. Long molecule chains associated with silk are the source of its strength – making it useful in fashion and beyond. Airbus, for example, is exploring whether planes could be made of a synthetic version of spider’s silk, radically reducing weight and thus fuel requirements.
The agriculture and food sector is another resource-hungry, high-emission area looking at synthetic biology. Alternative protein start-ups Beyond Meat, Impossible Foods and Better Dairy are all using synthetic biology techniques to produce meat and dairy substitutes at a fraction of the emission and environmental footprint of the conventional kind.
Other firms are building micro-warriors for environmental clean-up. Allonia, a waste remediation company spun off from Gingko Bioworks, engineers microbes to “eat” per- and polyfluoroalkyl substances (PFAS), a class of chemicals found in many products and manufacturing processes that resist breakdown and can have adverse health effects. Bayer and BASF are among corporate giants working with or acquiring synthetic biology start-ups to help the chemicals and agriculture industries maintain output while slashing their environmental toll.
Manufacturing nature
The lead markets for synthetic biology currently are the UK, US, Singapore and China, but engagement is global. A powerful engine for progress, according to Tom Knight, co-founder of Gingko Bioworks, who has been in the industry since its inception in the mid-1990s, is the International Genetically Engineered Machine (iGEM) foundation. Its synthetic biology competition draws thousands of entries per year, with participation from Africa to Japan, Korea to Mexico. Multiple interviewees for this article highlighted the competition as critical for innovation. “A lot of people in synthetic biology have come through that programme,” says Knight. The big global challenges outlined in the UN’s Sustainable Development Goals, he adds, are another focal point concentrating the next generation of researchers.
The key goal now for the synthetic biology field is for materials to become more reliable and reproducible. Professor Kitney sees parallels with the semiconductor industry in the 1960s, when it faced challenges like noise and reliability. Research and development in that sector “squeezed those problems out of the equation.” The synthetic biology industry should similarly benefit from the presence of more “bio foundries,” according to Professor Kitney. These are akin to factories that apply automation and standardisation, via high-throughput processing equipment, to enable prototyping, experimentation and mass production of synthetic biology products.
Despite the optimism, the sector does have its challenges. Past “bio” hype cycles have disappointed. The biofuels revolution, for instance, has not met expectations (accounting for a mere 0.1 per cent of global aviation fuel consumption in 2018). Problems include unrealistic timelines from venture capitalists and a lack of price competitiveness against oil. Some of the same over-hyped investment cycles could affect synthetic biology startups, but the prize warrants the effort, says Widmaier. “When this kind of revolution works, whole economies are transformed; just look at the semiconductor industry that created Silicon Valley, that changed the world”.
