Current Members

Our Principal Investigator

Prof. 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

Sabine Brinkmann-Chen, Ph.D.

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 likes the Denver Broncos, when they’re losing.

Hometown: Raider Nation (USA)

Our Postdoctoral Fellows

Edwin Alfonzo, Ph.D.

NIH Ruth L. Kirschstein NRSA Postdoctoral Fellow

B.S. in Chemistry, University of Massachusetts Lowell
Ph.D. in Chemistry, Boston University

Edwin’s doctoral studies involved the total synthesis of Lignan natural products and the development of new photoredox catalysts for their application thereof. When not in the lab, Edwin enjoys dancing, cooking, and cheering on all Boston teams.

Hometown: Lawrence, MA (USA)

Hayden Carder, Ph.D.

Arnold O. Beckman Postdoctoral Fellow

B.S. in Chemistry, University of Rochester
Ph.D. in Chemistry, MIT

Hayden obtained his Ph.D. at MIT under the guidance of Prof. Alison Wendlandt. During his doctoral studies, he worked on the development of radical tools to transform biomass sugars into rare sugars. Now in the Arnold Lab, he is excited to work with a diverse team to develop new-to-nature enzymatic activity. Outside of chemistry, Hayden enjoys cooking, hiking, and building things in his spare time.

Hometown: Chicago, Illinois (USA)

Jae Kennemur, Ph.D.

NIH Ruth L. Kirschstein NRSA Postdoctoral Fellow

B.S. in Chemistry, Texas Tech University
M.S. in Chemistry, University of Illinois, Urbana-Champaign
Ph.D. in Chemistry, Max-Planck-Institut für Kohlenforschung

Jae conducted her PhD studies in Ben List’s group at the MPI für Kohlenforschung in Germany, where they developed extremely acidic chiral organocatalysts for applications in a myriad of asymmetric transformations. Inspired by the remarkable ability of enzymes to impart regio- and stereoselectivity, Jae moved to the Arnold group to learn how to use protein engineering techniques to develop new-to-nature transformations. Outside of the lab, Jae enjoys exploring LA’s prolific stand-up comedy scene and figuring out new ways to live a more sustainable, low-waste life.

Hometown: Grand Prairie, TX (USA)

Ziqi Li, Ph.D.

B.S. in Chemistry, Nankai University
Ph.D. in Chemistry, Scripps Research

Ziqi conducted her Ph.D. research with Prof. Keary M. Engle at Scripps Research, where she explored how ligand design, reagent development, and synergistic catalysis enable regio- and enantioselective alkene functionalization. As a postdoc in the Arnold lab, Ziqi is excited to unlock the biocatalysis territory for the development of selective, efficient, and sustainable synthetic methodologies. Outside the lab, Ziqi enjoys all kinds of natural fragrances, coffee and tea included.

Hometown: Heze, Shandong (China)

Ariane Mora, Ph.D.

Schmidt Science Fellow

B.E. in Electrical and Computer Engineering (Hons), The University of Queensland
Ph.D. in Bioinformatics, The University of Queensland

During her PhD Ariane developed generative models of epigenetics in development and disease. She is excited to be part of the multi-disciplinary Arnold team and aims to engineer enzymes to tackle environmental issues. In her spare time Ariane enjoys bird watching, oil painting, and rock climbing.

Hometown: Brisbane (Australia)

Julia Reisenbauer, Ph.D.

SNSF Postdoctoral Fellow

B.Sc. in Chemistry, ETH Zurich
M.Sc. in Chemistry, ETH Zurich
Ph.D. in Chemistry, ETH Zurich

Julia dedicated her doctoral years to advancing the field of nickel-catalyzed transfer hydrocyanation reactions under the guidance of Prof. Bill Morandi at ETH Zurich. Simultaneously, she actively contributed to the development of innovative skeletal editing strategies for N-heterocycles. After obtaining her Ph.D., Julia became a postdoctoral researcher in the Arnold lab, where she embarked on a journey to gain expertise in biocatalysis and molecular biology techniques. Beyond her research pursuits, you’ll often spot her outdoors, indulging in her passions for biking, hiking, and bouldering.

Hometown: Edlitz (Austria)

Casey Ritts, Ph.D.

American Cancer Society Postdoctoral Fellow

B.S. in University of Wisconsin–Madison, Biochemistry
Ph.D. in University of Minnesota – Twin Cities, Chemistry

During his doctoral studies, Casey researched aryne methodology and natural product synthesis under the advisement of Prof. Thomas Hoye at the University of Minnesota. He developed methods for making helical polyarenes using hypervalent main group species, and he also studied the biosynthesis of (+)-ottelione A. Casey now investigates new-to-nature biocatalytic processes for synthesizing medicinal compounds. Outside of lab, Casey explores LA’s music scene, hikes, and hones his mixology skillset.

Hometown: Minneapolis, MN (USA)

Kathleen Sicinski, Ph.D.

NIH Ruth L. Kirschstein NRSA Postdoctoral Fellow

B.S. in Biochemistry, Moravian College
Ph.D. in Chemistry, Tufts University

Katie obtained her Ph.D. at Tufts University under the advisement of Prof. Krishna Kumar. Her doctoral work focused on chemical strategies to increase protease stability of peptide hormones for the treatment of non-communicable diseases such as type II diabetes, obesity, and Alzheimer’s disease. Now in the Arnold laboratory, Katie is harnessing the power of enzymes and directed evolution to engineer biocatalysts for chemical transformations that are hard to achieve by traditional synthetic methods. When not in the laboratory, you can find Katie teaching yoga, on the dance floor, or spending time with her four nieces and six nephews.

Hometown: Allentown, PA (USA)

Ziyan Zhang, Ph.D.

B.S. in Chemistry, Beijing Technology and Business University
Ph.D.  in Chemistry, The University of Texas at Dallas

Ziyan obtained her Ph.D. at The University of Texas at Dallas under the guidance of Prof. Vladimir Gevorgyan. During her doctoral studies, she focused on the development of denitrogenative transformations of pyridotriazoles and photoinduced palladium hydride-catalyzed reactions. Currently, as a postdoc in the Arnold laboratory, Ziyan is unlocking the power of enzymes and directed evolution for developing new-to-nature transformations. Outside of the lab, Ziyan enjoys reading, cooking, and hiking.

Hometown: Heze, Shandong (China)

Our Graduate Students

Deirdre Hanley, G2


University of California-Berkeley

During her undergraduate studies, Deirdre utilized artificial metalloenzymes and FRET techniques to develop ratiometric protein-based oxygen sensors. Following her work on protein functionality, she joined Caltech to employ directed evolution in the search for novel enzyme functions. In her free time, Deirdre enjoys hiking, collecting houseplants, and exploring SoCal.

Hometown: San Francisco, CA

Ravi Lal, G5

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)

Francesca-Zhoufan Li, G4


Amazon AI4Science Fellow

B.S. in Bioengineering and B.S. in Chemical Biology, University of California-Berkeley

Before joining the Arnold Lab, Francesca worked on a wide range of synthetic biology and protein engineering projects. Currently, she is a part of the ML subgroup. Outside of the lab, Francesca is active in DEI advocacy and enjoys staying active especially outdoors, puzzles (giant jigsaw and killer Sudokus), and iPhoneography.


Yueming Long, G3


B.S. Medicinal Chemistry, Wake Forest University

Yueming is passionate about exploring novel activities in metalloenzymes and harnessing the power of long-range sequencing technologies to gather sequence-function data. She is interested in learning and applying new technologies into her daily life and research. When not in the lab, Yueming finds joy in cooking and playing with robotic projects.

Hometown: Shanghai


Ryen O’Meara, G3

Chemical Engineering


B.S.E. in Chemical Engineering, University of Michigan-Ann Arbor

During undergrad, Ryen aided in the development of a novel discovery platform for agonist antibodies and applied it to the T cell receptor OX40. In the Arnold lab, he engineers enzymes to degrade emerging environmental contaminants. Outside of research, Ryen loves all forms of physical movement and wellness, cooking, baking bread, and reading literature.

Hometown: Canton, Michigan (USA)


Ziyang (Nick) Qin, G4


B.S. in Chemistry, University of Science and Technology of China

During his undergrad, Ziyang conducted research on both transition-metal catalysis and main-group catalysis. Being amazed by biocatalysis, he came to Caltech and joined the Arnold lab trying to develop novel transformations using engineered proteins. Outside the lab, Ziyang enjoys traveling, hiking, absorbing in art museums, hunting for delicious food.

Hometown: Chongqing, China


Jason Yang, G3

Chemical Engineering


B.S. in Chemical Engineering, Yale University

Jason studied materials for membrane separations using experiments, simulations, and machine learning during undergrad. He is now working in the ML subgroup to develop computational approaches to facilitate protein engineering. Outside of the lab, Jason enjoys electronic music, exploring new restaurants, and attempting to get better at beach volleyball.

Hometown: Wilmette, Illinois (USA)


Our Undergraduates and Visitors

Kamila Cano-Giraldo

Visiting Student Researcher — Biochemistry Beloit College

Kamila is an undergraduate at Beloit College (’25) majoring in Biochemistry. Her previous research has focused on the molecular mechanisms of cardiovascular diseases, particularly G-protein coupled receptor signaling and cardiac metabolism. During her time at the Arnold Lab, she hopes to explore different approaches to chemistry and gain a better understanding of the diverse possibilities offered by Heme proteins. In her free time, Kamila loves to paint, read, and lift weights.

Jan Heise

Visiting Student Researcher B.Sc. in Business Chemistry, Heinrich Heine University Duesseldorf

During his undergrad, Jan worked on strategies to increase the monodispersity of microgel systems to enable the creation of a model system to further investigate colloidal self-assembly. After that, Jan worked on the enantioselective synthesis of axially chiral carbazole derivatives. Outside of the lab Jan enjoys running and reading.

Hometown: Wildeshausen, Germany

Ana Jaramillo

Undergraduate Researcher – Bioengineering

Ana is an undergraduate at Caltech (’27) interested in biology. Her previous research has focused on the evolution of bacteria and viruses, and she is excited to continue this practice through the evolution of new biocatalysts that play a crucial role in the development of effective medicine. During her time at the Arnold Lab, she hopes to explore various ways in which enzymes can contribute to breakthroughs in medical applications and their accessibility to different communities. In her free time, Ana loves to read, play soccer, and go to the beach.

Hometown: Miami, Florida (USA)

Catherine Ko

Undergraduate Researcher – Chemistry

Catherine (’24) studies chemistry and biology at Caltech and has been part of the Arnold Lab since her freshman year. She has worked on stabilizing and promoting the evolution of new-to-nature biocatalysts. Through the Arnold Lab, she has gained hands-on experience with both the biological and chemical aspects of her projects. Beyond her studies and research, Catherine likes taking pictures, drawing/painting, playing badminton with friends, and planning enriching student life events through the Caltech Y.

Hometown: San Francisco, California (USA)

Ethan Lin

Undergraduate Researcher – Chemistry

Ethan is an undergraduate chemistry major at Caltech (class of 2026). He is interested in the intersection of biochemistry and organic chemistry. In his free time, Ethan enjoys cycling (including unicycling) and bird photography.

Hometown: San Diego, California (USA)

Orna Mukhopadhyay

Undergraduate Researcher – Bioengineering

Orna is an undergraduate at Caltech majoring in bioengineering (’27). She is interested in the interesection between biology, chemistry, computer science and mathematics, and she is excited to start research in the Arnold lab on evolving biocatalysts for multi-substrate directed evolution. She is excited to explore the intersection between biocatalysis and personalized medicine. In her free time, Orna enjoys reading, playing the violin, dancing, and exploring different eateries in LA/Pasadena with her friends.

Hometown: Baton Rouge, Louisiana (USA)

Sophia Wu

Undergraduate Researcher – Bioengineering

Sophia is an undergraduate student at Caltech (’25) majoring in bioengineering. Her research explores the evolution of novel biocatalysts to perform chemical transformations. Through biocatalysis, she hopes to solve synthetic challenges. Outside of lab, Sophia is involved in Caltech’s Fluid & Dynamics a cappella group. She enjoys karaoke and playing the cello and piano.

Hometown: Boston, Massachusetts (USA)