Sarah Kwartler

Sarah Kwartler
My lab introduced me to a realm of science that I hadn’t previously considered: manipulating molecular biology to counter human and environmental health hazards.


Biology '21

Project Team

The Oregon coast’s tide pools are one of my favorite places in the world. Peering in, you would see the sculpin sleekly swimming, swaying anemones with feathery hats and plastic.

Plastics are ubiquitous. Although plastics were initially celebrated for their durability, their accumulating waste pose an environmental and human health hazard. While decreasing reliance on plastics may yield long-term benefits, sustainable and efficient remediation is needed now. Biodegradation is an innovative method for countering the plastic pandemic.

To identify plastic degraders, scientists have investigated bioremediation potential in organisms that thrive in environments with high concentrations of plastic waste as well as organisms that break down naturally occurring polymers. Some invertebrates, like beeswax-consuming Galleria mellonella, are capable of degrading plastic independently from their gut microbiota. This impressive process inspired my analysis of G. mellonella’s plastic biodegradation rate to assess whether it would be a practical solution. Unfortunately, G. mellonella’s plastic consumption rate is too slow for them to be a successful solution akin to at-home worm composting bins.

In a different case, the plastic-degrading bacteria Ideonella sakaiensis was isolated from a polyethylene terephthalate contaminated sample. Its two-step enzymatic process was able to degrade polyethylene terephthalate (PET) films in six weeks. I. sakaiensis’ enzymes require improvement to degrade thick, crystalline PET. I explored a CRISPR-based approach to directly modify the plastic-degrading enzyme (PETase) gene in E. coli. Using CRISPR/Cas9 EvolvR, I was able to create single-nucleotide mutations in the PETase gene at one of the enzyme’s active sites. Sadly, COVID-19 shutdowns put this research on indefinite hold before I was able to test the mutated PETase. However, further selection and bioengineering of both bacterial and invertebrate systems for improved plastic degradation capacity may have the potential to mitigate our plastic pollution crisis.  

I am grateful for the support of the Bass Connections Student Research Award and the opportunity to be a part of the Bioremediation of Plastic Pollution to Conserve Marine Biodiversity team. Beyond taking part in groundbreaking research, I was welcomed into a thoughtful and supportive community. Our team’s strength was our diverse experience, backgrounds and interests. Our lab meetings helped us question future steps and advise one another from perspectives that we may not have considered coming from our respective fields.

When COVID-19 shutdowns began, our team leaders led by example in how to be flexible with research plans. Their support helped us reframe many projects to adapt to a virtual world. I learned from my teammates how to utilize bioinformatics, so that I could continue working from Oregon. During a hectic remote fall semester, our weekly meetings were a chance to check in with friends and maintain a semblance of normalcy.  

Most importantly, my experience with my Bass Connections team encouraged me to take risks. My lab introduced me to a realm of science that I hadn’t previously considered: manipulating molecular biology to counter human and environmental health hazards. Although I am graduating, I am grateful that I will still be a part of our team’s community. As I head to Princeton in the fall to begin my Ph.D. in molecular biology, I am excited to see what our team will discover. 

June 2021