Complex circuits
Voigt, who is co-directing MIT’s new Synthetic Biology Center, is now working on building larger, highly interconnected systems that include sensors and circuits that can respond to sensors’ input.
“Right now we’re integrating components into an individual cell. One of the problems with that is getting all of the pieces to interact with each other,” he says. Another challenge is preventing pieces that are not supposed to interact from doing so.
“If you want to create a system with 50 circuits that are all working together as part of a computation that the cell is running, then you need each one of those individual circuits to not interfere with all the others. So it becomes an exponentially challenging problem to build each additional new circuit and show that it doesn’t interact with all the others,” Voigt says.
Such complex circuits could form the basis of microbes that can regulate their own fermentation processes — for example, the yeast that ferment biomass into ethanol, Voigt says. Ethanol fermentation produces acetate, which is toxic to yeast, as a byproduct. Therefore, fermentation vats must be equipped with sensors that detect dangerous acetate levels and take corrective action, such as slowing down delivery of the microbes’ food supply (glucose).
Using synthetic biology, it’s possible that this monitoring process could be transferred into the cells themselves. Yeast cells would sense the elevated acetate levels and shut off their own glucose transporters until acetate levels go down again.
Voigt says he came to MIT in part because of its focus on biological engineering as a way to impact a variety of fields — not just medicine but also agriculture, energy, industrial chemistry, environmental cleanup and materials. To that end, the new Synthetic Biology Center has recruited researchers from a wide range of backgrounds.
“Our hope is that this place really brings together different people with the same objectives who can think innovatively about the types of systems we can design,” Voigt says.
