Evolution, to me, is the best designer of all time.

Isobutanol is not a natural product, but we evolved an enzyme that makes it possible to convert plant sugars to this precursor to jet fuel.

We all need friends, and friends are there to hold you up when nothing else can.

I'm interested in using evolution to move forward into the future, to get biology to do a lot of new chemistry for us.

I know how to do science. I know how to make things. I don't know how to run a company. Now that's a really tough job.

I love what I do, and I'm grateful for every day I can do it.

Human beings have been manipulating the biological world for thousands of years without understanding how DNA codes function.

Bemoaning your fate is not going to solve the problem.

I wanted to rewrite the code of life, to make new molecular machines that would solve human problems.

I took mechanical drawing, geometry and typing at high school, the latter because that is what they did with smart girls in those days!

In the test tube, I can make any DNA I want, recombining it from monkeys, worms, anywhere. So I can explore new rules of breeding with molecules.

Evolution is good for optimising and that is well understood. But evolution also creates things that no one knew were even possible.

Microbes such as bacteria and yeast use enzymes to make fuels from biomass. We use directed evolution to perfect those enzymes and make new fuels efficiently.

The code of life is like a Beethoven symphony. We have not yet learned how to write music like that. But evolution does it very well. I am learning how to use evolution to compose new music.

I wanted to make enzymes that would solve human problems, not just problems for a cell that makes them.

Enzymes catalyze all the reactions of life. They're what allow you to extract materials and energy from your environment and turn that into muscle and tissue and fat. That's all done by enzymes. They're pretty remarkable chemists - they're even better than Caltech chemists.

Engineering the biological world was even more interesting than engineering the mechanical world.

My feeling is that we can genetically encode almost any kind of chemistry. We just have to learn how to do that.

What I want to do is demonstrate that biology can learn how to make a vast array of molecules that people thought were outside the realm of biology.

For me, I was always the only woman in my cohort, first as a mechanical engineering undergraduate student, then as a chemical engineering graduate student. There were very few women getting degrees in those fields at the time. My role models were men - great men role models.

Doing science at the highest level is hard for anyone. It's hard for women, and it's hard for the men. And we need to have supportive mentors and role models we can look up to.

Most innovative things are not obvious to other people at the time. You have to believe in yourself. If you've got a good idea, follow it even though others tell you it's not.

I meet so many young people who want to plan out their lives and want a recipe. They want me to tell them how to succeed. I didn't follow a recipe. I followed my instincts.

I learned how to navigate the world, and life's potholes, in Pittsburgh.