Current Members

Our Principal Investigator

Dr. Frances Arnold

Linus Pauling Professor of Chemical Engineering, Bioengineering, and Biochemistry
Director of the Donna and Benjamin M. Rosen Bioengineering Center
2018 Nobel Laureate in Chemistry

B.S. Princeton University
Ph.D. University of California-Berkeley

Frances has spent her life convincing enzymes to do interesting and useful things through directed evolution, a process of iterative mutagenesis and screening. Outside of the lab she keeps very busy, enjoying yoga, gardening, hiking, and cooking.

Hometown: Pittsburgh, Pennsylvania (USA)

Our Laboratory Staff

Dr. Sabine Brinkmann-Chen

Laboratory Manager

M.S. in Biology Saarland University
Ph.D. in Applied Microbiology, Saarland University

Sabine is the lab manager and staff scientist of the Arnold lab with a background in microbiology. She has been with the lab since October 2006. Outside of lab, she enjoys calisthenics training and Pilates.

Hometown: Saarbrücken, Germany

Cheryl Nakashima

Administrative Assistant

B.S., Wossamotta U.

Cheryl is the backbone of the Arnold Lab, and we don’t know what we would do without her. When she’s not organizing, she loves to create, collect and imagine all things art. A fun fact about Cheryl is that she loves the Denver Broncos, when they’re losing.

Hometown: San Jose, CA (USA)

Our Postdoctoral Fellows

Dr. Soumitra Athavale

B.S./M.S. in Chemistry and Biology, Indian Institute of Science Education and Research (IISER) Pune
Ph.D. in Chemistry, University of Illinois-Urbana Champaign

Soumitra’s Doctoral research in the Scott E. Denmark group focused on organic synthesis and elucidation of mechanistic pathways in asymmetric autocatalytic reactions. His research interests are in organic synthesis, biocatalysis and molecular evolution. As a postdoc in the Arnold lab, Soumitra is interested in harnessing the catalytic potential of iron enzymes to push the frontiers of synthetic methodology as well as to gain a fundamental mechanistic understanding of this enzymatic process. Outside the lab, Soumitra enjoys reading, music and solving synthetic chemistry puzzles.

Hometown: Pune, India

Dr. Noah Dunham

NIH Ruth L. Kirschstein NRSA Postdoctoral Fellow

B.S. in Biology, East Stroudsburg University
Ph.D. in Biochemistry and Molecular Biology, Pennsylvania State University

During his graduate work, Noah studied the mechanisms of non-heme iron-dependent enzymes. He is currently working on expanding heme-catalyzed carbene-transfer reactions with engineered cytochromes P450, as well as exploring new reactivity with other biological cofactors. Outside of the lab, he enjoys volleyball, basketball, hiking, climbing, and ballroom dance.

Hometown: Reeders, Pennsylvania (USA)

Dr. Benjamin Levin

NIH Ruth L. Kirschstein NRSA Postdoctoral Fellow

B.S. in Biochemistry and Mathematics, University of Michigan-Ann Arbor
Ph.D. in Chemistry, Harvard University

Ben has long been fascinated by enzymes and the reactions they catalyze. During his graduate studies, he discovered and characterized proteins found in the gut microbiota, and since then has been evolving new enzymes in the laboratory. The extended time at home has renewed his interests in cooking and reading.

Hometown: Oak Park, Michigan (USA)

Dr. Zhen Liu

B.S. in Chemistry, Peking University
Ph.D. in Chemistry, The Scripps Research Institute

Zhen earned his Ph.D. degree from The Scripps Research Institute, studying transition metal-catalyzed alkene and alkyne functionalization. He is currently a Postdoctoral Fellow in the Arnold lab, working on biocatalytic carbene and nitrene transformations. Outside of the lab, Zhen enjoys playing basketball, watching sports games, and watching anime.

Hometown: Xuzhou, Jiangsu (China)

Dr. David Miller

NIH Ruth L. Kirschstein NRSA Postdoctoral Fellow

B.A. in Chemistry, Johns Hopkins University
Ph.D. in Chemistry, Princeton University

David is broadly interested in organic synthesis & catalysis, with a strong emphasis on physical organic chemistry. Outside of lab, his hobbies include listening to music, reading fiction, and spending time outdoors.

Hometown: Wakefield, Massachusetts (USA)


Dr. Nicholas Porter

Helen Hay Whitney Postdoctoral Fellow

B.A. in Chemistry, Boston University
Ph.D. in Chemistry, University of Pennsylvania

Throughout his research career, Nick has maintained an interest in the structure-function relationships that underpin enzyme function. In the Arnold Lab, he works on projects related to enzymatic carbene transfer and eliciting new chemistry from metalloenzymes. Outside of the lab, he enjoys climbing, hiking, cooking, reading, and board games of any kind.

Hometown: Shrewsbury, Massachusetts (USA)

Our Graduate Students

Patrick Almhjell, G4

Biochemistry and Molecular Biophysics

B.S. in Medicinal Biochemistry, Arizona State University

During his undergraduate, Patrick used Rosetta to design self-assembling metalloproteins that contained noncanonical amino acids (ncAAs). Unwilling to stop working with ncAAs, he now works in the Arnold Lab to engineer enzymes that synthesize these molecules in a simple and sustainable manner. Patrick’s love of ncAAs is matched only by his love of the outdoors, where he enjoys climbing, snowboarding, and camping.

Hometown: Phoenix, Arizona (USA)


Shilong (Gregg) Gao, G3


B.A. in Biochemistry and Molecular Biology,  Boston University

During his undergrad, Shilong worked on natural product synthesis and re-modification. In the Arnold lab, he is currently working on nitrogen-transfer reactions. Shilong enjoys weight-lifting, playing guitar, and video games.

Hometown: Beijing, China

Nat Goldberg, G5


A.B. in Chemistry, Harvard College

As an undergraduate, Nat worked in organofluorine chemistry with Prof. Tobias Ritter. When he arrived at Caltech he realized that biocatalysis is the future, so he joined the Arnold lab where he explores non-native activities of metalloenzymes. Outside the lab, Nat enjoys playing the tuba and wilderness canoeing.

Hometown: Durham, North Carolina (USA)


Kadina Johnston, G3

NIH Biotechnology Leadership Training Program

B.S. in Biomedical Engineering and Chemistry, University of Wisconsin-Madison

During undergrad, Kadina studied Sis1, engineered biosensors at Promega, and later designed nanoparticles for drug delivery. Currently she is a part of the ML subgroup and works on developing ML-based methods for directed evolution. Outside of the lab Kadina enjoys surfing, hiking, and climbing.

Hometown: Summit, Wisconsin (USA)

Ravi Lal, G2

Chemical Engineering

B.S. in Chemical Engineering, University of California-Berkeley

During undergrad, Ravi performed research in the Keasling lab, investigating domain swapping in modular type I polyketide synthases. He is currently using directed evolution methods to bring novel reactivities to the growing family of carbene transferase enzymes. In his free time Ravi enjoys watching basketball, hiking, and trying to find East coast quality pizza on the West coast.

Hometown: Ithaca, New York (USA)

Nicholas Sarai, G3

Biochemistry and Molecular Biophysics
NIH Biotechnology Leadership Training Program

B.S. in Biochemistry, University of Denver

After undergraduate research in organic synthesis and molecular biology, Nicholas spent two years at the National Renewable Energy Laboratory focused on thermophilic enzymology and metabolic engineering. Currently he is engineering enzymes to degrade recalcitrant compounds. Nicholas devotes his time outside of lab to skiing and climbing.

Hometown: Saint Louis, Missouri (USA)


Lucas Schaus, G3

Biochemistry and Molecular Biophysics
AFR PhD Fellow

B.S. in Biology/Chemistry, ETH Zurich
M.S. in Biology/Chemistry, ETH Zurich

During his Masters, Lucas worked on various cyclopropanation methodology projects using Gold (I) and Iron (II) complexes as well as proteins known as protoglobins. Later he worked on computationally designed artificial metalloenzymes. Currently, a member of the machine learning subgroup, Lucas works on learned protein embeddings, classifiers for two-enzyme systems and studies the non-natural activities of protoglobins. In his pastime, Lucas enjoys cooking, climbing, skiing and playing music.

Hometown: Niederanven, Luxembourg

Daniel Wackelin, G3

Chemical Engineering

B.S.E. in Chemical and Biomolecular Engineering, University of Connecticut

During undergrad, Daniel studied yeast surface display of proteins and improved mammalian cell expression of antibody derivatives. Now, he works on engineering carbene transferases to perform new-to-nature reactions. When not in lab he enjoys hiking, camping, and board games with friends.

Hometown: Farmington, Connecticut (USA)

Ella Watkins-Dulaney, G5


B.S. in Cell and Molecular Biology at The University of Texas at Austin

Ella began her research career on the 2014 University of Texas iGEM team studying noncanonical amino acid (ncAA) synthetase fidelity and efficiency. She then worked with in Andrew Ellington’s lab adapting emulsion PCR-based directed evolution methods to be compatible in S. cerevisiae. At Caltech, she combined her fascination for ncAAs with her interest in directed evolution and now engineers the tryptophan synthase to create new ncAAs. Outside of lab, Ella loves to rock climb, cross-stitch, and play D&D with friends.

Hometown: Allen, Texas (USA)


Bruce Wittmann, G4


B.A. in Chemistry and Biochemistry, Washington University in St. Louis

During undergrad, Bruce studied far-red chlorophylls and their potential agricultural and biotechnological applications. He then spent two years working at the synthetic biology company, Intrexon, before joining the Caltech bioengineering PhD program in 2017. Bruce is a member of the machine learning subgroup in the Arnold Lab, and his current research focuses on navigation of combinatorial fitness landscapes. Outside of lab, Bruce enjoys hiking and brewing beer.

Hometown: Chicago, Illinois (USA)


Juner Zhang, G4


B.S. in Chemistry and Chemical Biology, Tsinghua University

During undergrad, Juner studied the biophysics of small circular ssDNA, and its role in rolling cycle replication. In the Arnold lab, he is developing new enzymes for new-to-nature C–H functionalization reactions using directed evolution. Outside of the lab, Juner enjoys climbing, fencing, and hiking.

Hometown: Xian, China

Our Undergraduates and Visitors

Nayla Abney

Undergraduate Researcher – Chemical Engineering

During undergrad, Nayla has been studying and aiding in engineering CYP3A4 and BM3 to perform CH sp3 alkylation. Outside of the lab, Nayla enjoys playing soccer for Caltech, reading, and exploring the LA area.

Hometown: Deptford, New Jersey (USA)

Grace Liu

Undergraduate Researcher – Bioengineering

Grace is an undergraduate student majoring in bioengineering at Caltech. Her research involves using machine learning to analyze protein data. Outside of school and research, she enjoys writing, skiing and watching musicals.

Hometown: Toronto, Canada

Davíd Medina Ortiz

Visiting Graduate Student, Universidad de Chile
Ph.D. Fellowship Conicyt, Chile, Number 21181435

B.S. in Bioinformatics Engineering,Universidad de Talca

David is a Ph.D. (c) in engineering sciences, at Universidad de Chile. His main research topics are the design and implementation of predictive models applied to protein engineering. Currently, he is a visiting student researcher and part of the ML subgroup. David loves to play guitar and take night walks.

Hometown: Santiago, Chile


Amy Wang

Undergraduate Researcher – Chemical Engineering

As a senior undergrad at Caltech, Amy is majoring in chemical engineering on the processes track. She is currently working under her mentor Ella Watkins on the TrpB team. Outside of the lab, Amy enjoys basketball, tennis, singing, and photography.

Hometown: Colorado Springs, Colorado (USA)

Andrew Zhou

Undergraduate Researcher – Chemistry

Andrew is an undergraduate majoring in chemistry with a minor in biology. He works on engineering carbene transferases to be novel biocatalysts. Outside of the lab, Andrew is the president of the Chemistry Club, he enjoys playing tennis and the cello, and he was a member of the intercollegiate tennis team.

Hometown: La Jolla, California (USA)