Julie Maresca, Ph.D.

Associate Professor, Principal Investigator

Julie got a PhD in Biochemistry, Microbiology, and Molecular Biology from Penn State University, working with Don Bryant on the genetics and physiology of pigment biosynthesis in photosynthetic green sulfur bacteria. She then did postdoctoral research with Ed DeLong at MIT, working on metagenomic and metatranscriptomic analysis of marine microbial communities. She now uses genetics, physiology, and meta-omics techniques to learn more about microbes in natural and engineered environments: how they use light, how they obtain nutrients, and what they are doing in the sometimes-strange places where we find them.




Priscilla Hempel

PhD Student

Priscilla received her bachelor’s degree in Bioinformatics and Molecular Biology from Rensselaer Polytechnic Institute and joined the lab in 2015. Her work focuses on identifying similarities among Actinobacterial genomes as well as changes in signaling and transcriptional regulation that explain changes in gene expression associated with light availability. Priscilla is an NSF IGERT Fellow of University of Delaware’s Systems Biology & Engineered Environments IGERT Program. In addition to her work, Priscilla is also an active board member of University of Delaware’s Bioinformatics Student Association. She also enjoys gardening, playing board games, and cooking.




Anders Kiledal

PhD Student

Anders received his bachelor’s degree in Biology from Hillsdale College and joined the lab in 2016. His work focuses on bacteria in concrete, how communities change over time and reflect concrete composition. Anders is a DENIN Environmental Fellow and PhD student in the Molecular Biology and Genetics concentration of the Department of Biological Sciences. He is an active member of the Biology Graduate Student Association, and outside of the lab enjoys consuming coffee, running/hiking, and photography.




Emma Smith

MCE Student

Emma received her bachelor’s degree in Chemical Engineering from Case Western Reserve University and joined the lab in 2018. Her research focuses on per-fluorinated alkane remediation using light-activated nanoparticles to break up long carbon chains and microbes to split the carbon-fluorine bonds. She is a master’s student in the Environmental Engineering program and is a member of UD’s student chapter of the American Water Resource Association. Outside of the lab and academics, she enjoys gardening, traveling, and baking some mean blackberry cheesecake.






As far as we know, Microbes arrived on earth 3-4 billion years ago. They were founding members of the lab and continue to contribute to each of the current projects. While in the Maresca Lab they can simultaneously be found everywhere. Microbes have a diverse set of interests, some more evident and/or agreeable than others. Shown here are red colonies of Serratia isolated from soil.






Postdoctoral Scholars

Jessica (Keffer) Clinton

Jessica got her PhD from the Georgetown University/NIH joint program, working with Carol Bewley on the characterization of bioactive compounds from tropical sponges. In the Maresca lab, she developed a microscopy assay to visualize bacteria with active rhodopsins (these papers) and characterized the rhodopsin from the freshwater Actinobacterium Rhodoluna lacicola (here). She is currently working in the Geology department at UD.









PhD Students

Mengyin Yao

Mengyin got her PhD in Civil and Environmental Engineering in 2016. She isolated bacteria from an extremely oligotrophic lake, and her research showed that these bacteria have several mechanisms for either acquiring phosphorus from diverse sources, or surviving long-term with very little phosphorus (here). She also showed that methane may be one of the byproducts of phosphorus acquisition in these bacteria (here).




Kehui (Keira) Zhang

Keira contributed to the development of the method for extraction of DNA directly from concrete (later published here).












MS Students

Archana Singh

MS Student

Archana received her Master’s degree in Cell Biology and Organ Systems from UD in 2019. She joined the lab in 2016 and her work focused on quantifying different cellular activities in light-responsive and non-light-responsive Actinobacterium bacterial cells to demonstrate how they respond to light at a physiological level. She is currently a Scientist III at Eurofins Lancaster Laboratories.





Christine Chapman

Christine received her bachelor’s degree in biology with a concentration in microbiology from West Chester University of Pennsylvania and she joined the lab in 2016. Her work focused on the role of microbes in soil aggregation in roadside soils amended with biochar for the purpose of stormwater management.




Kelsey Miller

Kelsey got her MS in Biology from UD in 2016, using qPCR and TIRF microscopy to characterize microbes that encode rhodopsin genes and produce active rhodopsins in the Chesapeake Bay (here). She is currently a senior research associate at Kaleido BioSciences.






Valentina (Beneski) Miller

Tina got an MCE in Civil and Environmental Engineering in 2013. Her thesis research characterized nutrient leaching from biochar, which we are investigating for use in stormwater filters. This work was published here and is being continued by Christine Chapman. Tina is now a senior staff engineer at Langan.











Research Associates and Visiting Scholars

Jessica (Keffer) Clinton

Monica Numpaque


Undergraduate Students

  • Jordan Heydt
  • Shannon McDermott
  • Hannah Tompkins
  • Eric Rouviere, University of Delaware Quantitative Biology/Physics, Class of 2018. Using
    TIRF microscopy to estimate single-protein rhodopsin fluorescence.
  • Steven Olson, University of Delaware Biology, Class of 2018. DNA photolyase activity in
    Actinobacteria. January 2016 – December 2016.
  • Natalie Muneses, University of Delaware Biomedical Engineering, Class of 2018.
    Developing a microscale cell-sorter. January 2016 – December 2016.
  • Dianna Kitt, University of Delaware Civil and Environmental Engineering, Class of 2017.
    Biophysical consequences of lipid remodeling in phosphate-starved bacteria. June 2015 –
    June 2017. DENIN Environmental Scholar (2015-2016), Senior thesis.
  • Katherine Dillon, University of Delaware Biological Sciences, Class of 2016.
    Actinorhodopsin oligomerization and its effect on bacterial membrane integrity. Summer
  • Alison Treglia, University of Delaware Civil and Environmental Engineering, Class of 2018.
    Carotenoid-enhanced tolerance of oxidative stress in bacteria isolated from concrete.
    November 2014-December 2016. DENIN Environmental Scholar (2014-2016).
  • Sarah Yannarell, University of Delaware, Chemistry and Biochemistry, Class of 2015.
    Bacterial-fungal interactions in soil. June 2013 – June 2015. Senior thesis.
  • Elena Dadukova, University of Delaware Civil and Environmental Engineering, Class of
    2015. Analysis of a colorless mutant of Rhodoluna lacicola. Spring 2014. CIEG 461 credit.
  • Danielle Weader, University of Delaware Civil and Environmental Engineering, Class of
    2015. Vampire bacteria in an ultra-oligotrophic lake. Spring 2014. CIEG461 credit.
  • Andrew DiPietro, University of Delaware, Chemical Engineering, Class of 2015.
    Relationship between pigmentation and agar degradation in a marine bacterium. Summer
    2013 – Spring 2014.
  • Paul Moser, University of Delaware, Civil and Environmental Engineering, Class of 2015.
    Microbial populations on concrete. Fall 2012 – Spring 2014.
  • Joseph V. Kerridge, University of Delaware, Chemical Engineering, Class of 2015.
    Degradation of organic components of asphalt. Spring – Summer 2013.
  • Mary Katherine Sutter, University of Delaware, Civil and Environmental Engineering, Class
    of 2014. Alkalitolerant microbial populations on concrete. Fall 2011 – Spring 2012.
  • Samayyah Williams, California State University at Pomona, Civil Engineering Class of 2013.
    Summer 2012.
  • Julianne Page, University of Delaware Civil and Environmental Engineering Class of 2012.
    Bacterial population analysis in Canadian oil sands tailings ponds. June 2011 to June 2012.
  • Brittany Debord, University of Delaware Civil and Environmental Engineering Class of
    2012. Archaeal population analysis in Canadian oil sands tailings ponds. June 2011 to June
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