Engineered algae puts half of its carbon into fats for biofuels

Enlarge / This raceway pond is used for continuous growth of biofuel-producing microbes. (credit: RFE Renewable Fuel & Energy/Sandia National Lab)

There’s an inherent tension in convincing organisms to produce fuel for us. To grow and thrive, the organism has to direct its energy into a variety of chemicals—proteins, fats, DNA, and more. But for biofuels, we’re mostly interested in fats, which are long-chain hydrocarbons that already look a lot like our liquid fuels. Fat is easy to convert into biodiesel, for example.

So how do we convince an organism to do what we want, rather than what it needs? There have been two approaches to this so far. One is to take an organism that we understand well and engage in genetic engineering to direct its metabolism toward fuel production. The second approach is to search for organisms that naturally produce lots of the chemicals we’re interested in.

Now, researchers at the company Synthetic Genomics have taken what you might consider a hybrid approach. They’ve started with an algae that will produce oodles of fat, but only if you stop its growth by starving it of essential nutrients. And, by studying how this starvation response works, the scientists identified a key regulator and altered its activity. The engineered strain produces nearly as much fat as the normal strain, but it does so while continuing to grow.