I’ve spent most of the last 2 weeks ragging on a few of the hottest SynBio startups. I’ve pointed out that these synbio startups have a very difficult path to profitability, and some might not even have a working business model. But from the scientific side, there’s still a revolution out there for synthetic biology, and I want to explain it.

To start with, the insulin and drug products revolution is a definite win for synthetic biology. The ability to take any gene, clone it into a bacteria or yeast cell, and then express it and collect the product is what has made many drugs so much cheaper than they were decades ago when we had to extract the drugs from animal carcasses or massive amounts of plant matter. It has also allowed revolutions in the types of drugs we can study and offer to patients, just about any protein you can think of could be turned into a drug that is usable for patients. Antibodies are a special type of protein which can also be produced through synthetic biology, and many antibody products have hit the drug market to treat all kinds of diseases. Aducanumab is one such antibody, a much hyped drug for treating (or rather slowing the progress of) Alzheimer’s disease. Quick note: you can tell if a drug contains an antibody by it’s name: aducanumab’s name ends in “mab” which stands for “monoclonal antibody.” Gemtuzumab (AML drug), Tezepelumab (severe asthma), pretty much any drug who’s name ends in “mab” is an antibody drug, and almost always they are produced through synthetic biology.

Biology can also catalyze certain reactions that chemistry can’t easily do. The classic example of this is creating molecules with specific stereochemistry. This will be a bit technical, but consider your left and right hand: they both have 4 fingers and a thumb but they are mirror images of each other, you can’t put your left hand in a right-handed glove and vice versa. In chemistry we would call left and right hands “stereoisomers” of each other, and just as with hands and gloves you can’t put left-handed molecules into places that require right-handed molecules. But chemically stereoisomers are identical, they have almost the exact same chemical properties and so a reaction which produces one stereoisomer will usually produce all possible stereoisomers in equal amounts. Image you wanted to produce only right hands, your starting material is the assembled 4-finger-plus-palm, now you just have to add the thumb in the correct place. Ignoring that the 4 fingers are of unequal length, if you put the thumb on one side of the fingers you get a right hand, while if you put the thumb on the other side of the fingers you get a left hand. A chemical reaction will make an equal number of right hands and left hands because it will add the thumb randomly to both sides. A reaction catalyzed by an enzyme however will only put the thumb on one side, the side you picked, and thus using an enzyme you can ensure you only make right hands and not left hands. This is another place where synthetic biology can be critical, there are many stereoisomers where one isomer is a useful drug and the other isomer may be a harmful chemical, we need to have some process to create only one of them and for that engineering enzymes with synthetic biology can yield good results.

Finally biology can greatly catalyze reactions in a way that greatly reduces the amount of energy we have to put into the system. Make no mistake, catalysis doesn’t yield free energy, but it does lower the energy barrier for a reaction. To turn carbon dioxide into some non-harmful form of carbon, we would chemically have to pump in a lot of energy to break the carbon-oxygen bonds which hold it together. That energy would require a high temperature and high pressure, which would then require containment, meaning scrubbing carbon from the atmosphere chemically is a very difficult process. However plants remove carbon dioxide every day, and do so at the modest temperatures and pressure that we find anywhere on Earth. They can do this because they use enzymes to catalyze the reaction, which lowers to energy barrier for the reaction to proceed forward. IF carbon capture technology ever becomes economically viable, mark my words it will have to be done using enzymes.

So synthetic biology allows us to tap into biological processes to perform jobs that are difficult to do chemically. The tools we have to do so, the genetic code of living organisms, also provide us with a vast array of starting tools to choose from to make things easier since we aren’t starting from scratch. And finally the fact that living organisms will grow and develop from things as simple as sugar instead of requiring oil or rare earth metals means that synthetic biology can be done just about anywhere and isn’t as limited by commodity costs like most other industries. In short, I DO believe synthetic biology may be the future, but I’m just not sure the current crop of biotech upstarts have what it takes