Frances Arnold

Frances Hamilton Arnold (born July 25, 1956) is an American chemical engineer and Nobel Laureate. She is the Linus Pauling Professor of Chemical Engineering, Bioengineering and Biochemistry at the California Institute of Technology (Caltech). In 2018, she was awarded the Nobel Prize in Chemistry for pioneering the use of directed evolution to engineer enzymes.

In 2019, Alphabet Inc. announced that Arnold had joined its board of directors. Since January 2021, she also served as an external co-chair of President Joe Biden's Council of Advisors on Science and Technology (PCAST).

Arnold is the daughter of Josephine Inman (née Routheau) and nuclear physicist William Howard Arnold, and the granddaughter of Lieutenant General William Howard Arnold. She has an older brother, Bill, and three younger brothers, Edward, David and Thomas. She grew up in the Pittsburgh suburb of Edgewood, and the Pittsburgh neighborhoods of Shadyside and Squirrel Hill, graduating from the city's Taylor Allderdice High School in 1974. As a high schooler, she hitchhiked to Washington, D.C., to protest the Vietnam War and lived on her own, working as a cocktail waitress at a local jazz club and a cab driver.

The same independence that drove Arnold to move out of her childhood home as a teenager also led to a large volume of absences from school and low grades. In spite of this, she made near perfect scores on standardized tests and was determined to attend Princeton University, the alma mater of her father. She applied as a mechanical engineering major and was accepted. Arnold's motivation behind studying engineering, as stated in her Nobel Prize interview, was that "[mechanical engineering] was the easiest option and the easiest way to get into Princeton University at the time and I never left".

Arnold graduated in 1979 with a Bachelor of Science (BS) degree in mechanical and aerospace engineering from Princeton University, where she focused on solar energy research. In addition to the courses required for her major, she took classes in economics, Russian, and Italian, and envisioned herself as becoming a diplomat or CEO, even considering getting an advanced degree in international affairs. She took a year off from Princeton after her second year to travel to Italy and work in a factory that made nuclear reactor parts, then returned to complete her studies. Back at Princeton, she began studying at its Center for Energy and Environmental Studies – a group of scientists and engineers, at the time led by Robert Socolow, working to develop sustainable energy sources, a topic that would become a focus of her later work.

After graduating from Princeton in 1979, Arnold worked as an engineer in South Korea and Brazil and at Colorado's Solar Energy Research Institute. At the Solar Energy Research Institute (now the National Renewable Energy Laboratory), she worked on designing solar energy facilities for remote locations and helped write United Nations (UN) position papers.

She then enrolled at the University of California, Berkeley, where she earned a PhD degree in chemical engineering in 1985 and became deeply interested in biochemistry. Her thesis work, carried out in the lab of Harvey Warren Blanch, investigated affinity chromatography techniques. Arnold had no chemistry background before pursuing a doctorate in chemical engineering. For the first year of her Ph.D. coursework, the graduate committee at UC Berkeley required that she take undergraduate chemistry courses.

After earning her Ph.D., Arnold completed postdoctoral research in biophysical chemistry at Berkeley. In 1986, she joined the California Institute of Technology as a visiting associate. She was promoted to assistant professor in 1986, associate professor in 1992, and full professor in 1996. She was named the Dick and Barbara Dickinson Professor of Chemical Engineering, Bioengineering and Biochemistry in 2000 and, her current position, the Linus Pauling Professor of Chemical Engineering, Bioengineering and Biochemistry in 2017. In 2013, she was appointed director of Caltech's Donna and Benjamin M. Rosen Bioengineering Center.