She is the Linus Pauling Professor of Chemical Engineering, Bioengineering and Biochemistry at the California Institute of Technology (Caltech).
[6] As a high schooler, she hitchhiked to Washington, D.C., to protest the Vietnam War[7] and lived on her own, working as a cocktail waitress at a local jazz club and a cab driver.
[8] 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.
[10] 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.
[11] 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.
[13] After graduating from Princeton in 1979, Arnold worked as an engineer in South Korea and Brazil and at Colorado's Solar Energy Research Institute.
[12] She then enrolled at the University of California, Berkeley, where she earned a PhD degree in chemical engineering in 1985[14] and became deeply interested in biochemistry.
[21] In 2000 Arnold was elected a member of the National Academy of Engineering for integration of fundamentals in molecular biology, genetics, and bioengineering to the benefit of life science and industry.
[15] In 2013, she and two of her former students, Peter Meinhold and Pedro Coelho, cofounded a company called Provivi to research alternatives to pesticides for crop protection.
[26] In January 2021 she was named an external co-chair of President Joe Biden's Council of Advisors on Science and Technology (PCAST).
She says her main job now is to help choose PCAST's additional members and to get to work setting a scientific agenda for the group.
"[27] Arnold is credited with pioneering the use of directed evolution to create enzymes (biochemical molecules—often proteins—that catalyze, or speed up, chemical reactions) with improved and/or novel functions.
[28] The directed evolution strategy involves iterative rounds of mutagenesis and screening for proteins with improved functions and it has been used to create useful biological systems, including enzymes, metabolic pathways, genetic regulatory circuits, and organisms.
In[28] her seminal work, published in 1993, she used the method to engineer a version of subtilisin E that was active in the organic solvent DMF, a highly unnatural environment.
[28][35] In addition to evolving individual molecules, she has used directed evolution to co-evolve enzymes in biosynthetic pathways, such as those involved in the production of carotenoids[36] and L-methionine[37] in Escherichia coli (which has the potential to be used as a whole-cell biocatalyst).
[28][38] Arnold has also used directed evolution to discover highly specific and efficient enzymes that can be used as environmentally-friendly alternatives to some industrial chemical synthesis procedures.
[28] She, and others using her methods, have engineered enzymes that can carry out synthesis reactions more quickly, with fewer by-products, and in some cases eliminating the need for hazardous heavy metals.
[39][40] At Caltech, Arnold runs a laboratory that continues to study directed evolution and its applications in environmentally-friendly chemical synthesis and green/alternative energy, including the development of highly active enzymes (cellulolytic and biosynthetic enzymes) and microorganisms to convert renewable biomass to fuels and chemicals.
A paper published in Science in 2019, with Inha Cho and Zhi-Jun Jia, has been retracted on January 2, 2020, as the results were found to be not reproducible.