microplastics

UConn Today features DMS graduate student Hannah Collins’ research into biodegradable plastics

Reposted from UConn Today by Sarah Al-Arshani | January 28, 2025

A study led by marine sciences Ph.D. student Hannah Collins found that Novamont’s Mater-Bi, a starch-based polymer, degraded significantly faster than traditional plastics—showing promise for reducing marine pollution

Plastic pollution has become a global crisis, with the United Nations Environment Programme estimating between 19 and 23 million tons of plastic waste leak into aquatic ecosystems each year. A partnership between UConn marine sciences researchers and a leading bioplastics manufacturer is showing promise in addressing this issue.

A recent study published in the Journal of Polymers and the Environment found that Mater-Bi, a starch-based polymer produced by Italian company Novamont, degraded by as much as nearly 50% over nine months in a marine environment—significantly more than traditional plastics.

Novamont, which has a U.S. office in Shelton, collaborated with the UConn team to evaluate the product’s biodegradation.

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Marine sciences Ph.D. candidate Hannah Collins and Larissa Tabb '22 evaluate the lab tanks to check on degradation progress. (Contributed by Hannah Collins)

 

The study was led by Hannah Collins, a marine sciences Ph.D. candidate. Collins and her co-author, Larissa Tabb ’22 (CLAS), highlighted research done as part of the Marine Environmental Physiology Laboratory under the guidance of her advisor, professor and head of marine sciences Evan Ward.

“I’ve always been interested in how marine animals interact with their environment,” Collins says. “When our lab started looking at microplastics, it was clear how pervasive and damaging this problem is.”

Collins says the findings could have meaningful implications for reducing plastic pollution in aquatic environments. For example, products like Mater-Bi could replace traditional plastics used in aquatic structures, such as kelp farm lines, to reduce the possibility of plastic pollution.

“We’ve seen the pictures of sea turtles with plastic around their heads,” she says. “We have a lot of evidence of the negative effects of plastic pollution.”

Collins, who grew up visiting Cape Cod and the beaches of Long Island Sound, has long been fascinated by marine life. After earning a degree in biology from Gettysburg College and working in Alaska’s salmon fisheries, she decided to combine her passion for marine organisms and the environment, first in her master’s program and now for her Ph.D.

She says the collaboration with Novamont has helped her feel like she is making a difference in addressing marine pollution. It also provided her with hands-on experience examining real-world product applications.

Biodegradable plastics like Mater-Bi degrade much faster than traditional plastics, reducing risks to aquatic environments. However, Collins notes that many of these products are often tested under controlled conditions, not in real-world marine environments.

Collins’ research on Mater-Bi was conducted in a semi-controlled environment at the John S. Rankin Laboratory on the Avery Point campus. The lab filters seawater from the surrounding area to keep large organisms, like crabs, out. This allowed Collins and her team to test how much the product degraded in natural conditions while ruling out the impact of interference from those large organisms.

Her team tested samples of a Mater-Bi compostable bag, a traditional plastic bag, and a known biodegradable plastic in the lab. Every two weeks, they checked and measured how much each sample degraded by either mass or area. After nine months, they found that the Mater-Bi samples lost between 25% and 47% of their mass or area. Additionally, they found that the rate of degradation increased during warmer months.

“Microbial activity tends to increase in warmer conditions, which likely contributed to the faster degradation rates we observed,” Collins says.

Collins says she is hopeful that these findings could lead to future uses of Mater-Bi in aquaculture, especially for products where temporary or disposable materials are often used, such as oyster grow-out bags or kelp farming lines.

“If something breaks loose, it won’t persist in the water for decades,” she says.

Collins and Tabb have maintained connections with Novamont. Collins will attend the World Aquaculture Conference in New Orleans this March, where she hopes to connect industry leaders with biodegradable products like those produced by Novamont.

“Addressing plastic pollution requires a range of solutions,” she says. “Biodegradable plastics are just one piece of the puzzle.”

Microplastics in Shellfish at “Extremely Low” Levels Globally

A group of researchers at DMS joined together under Sandra Shumway and Evan Ward, critically reviewed 750+ publications on microplastics and molluscs in the field and laboratory. This incredible effort has resulted in a thoughtful review of the cluttered scientific literature. Many studies on suspension feeding molluscs and microplastics have perpetuated inaccurate findings based on inappropriate methodologies, poor animal husbandry, and misinterpreted results. All of these false conclusions have caused a damaging narrative for the shellfish industry, raising concerns about the safety of eating shellfish. While microplastics are ingested by shellfish, microplastics in molluscs are extremely low globally as these animals are capable of selective capture, ingestion, and egestion of particles. In reality, the number of microplastics inhaled and consumed by humans in everyday life far outweighs the number of microplastics found in shellfish. Recommendations were provided for future studies in both the field and laboratory that will prevent researchers from falling into the pitfalls discussed in this review. This review is presented from the perspective of experts on shellfish physiology and represents the opinions of, and assessments made by, the authors. The authors hope this review can be used as a starting point for those interested in furthering this field of research with thoughtful experimental questions. Link to the article.

Sampling freshwater mussel gut microbiomes in the Great Lakes

In June 2022, Hannah Collins and Tyler Griffin from the Ward Environmental Physiology Lab went to Buffalo, NY, to perform research on the gut microbiomes of freshwater quagga mussels (Dreissena bugensis). The three-day trip involved collecting these invasive mussels from Lake Erie with the help of Brian Haas at the Buffalo State Great Lakes Center field station. The goal of the project, funded by an NSF Emerging Frontiers in Research and Innovation grant, was to sample mussel gut microbes before and after defecation with the goal of distinguishing between microbes that live inside the mussels and other microbes that were simply passing through. This work serves as preliminary research for the larger goal of investigating the feasibility of using freshwater mussels to remove microplastics from freshwater systems and co-concentration them with plastic-degrading bacteria.

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PhD student Hannah Collins taking samples of mussel guts for microbiome analyses (Photo: Tyler Griffin)

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Invasive Quagga mussels (Dreissena bugensis)

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View over the Niagara River in June 2022

DMS Kayla Mladinich shows that bivalves can reject microplastics

8 November 2022. DMS is happy to share the latest publication by PhD student Kayla Mladinich, showing the surprising but good news that blue mussels and oysters appear not to ingest all microplastic particles floating in the water.

By Kayla Mladinich.

Oysters and mussels are filter feeders that draw particles in from the surrounding water to be eaten. These animals can select which particles are eaten or rejected depending on factors such as particle size and surface properties. This study was performed to determine what kinds of microplastics will be consumed or rejected by oysters and mussels. Both species rejected larger microplastics more than smaller microplastics and did not differentiate between different types of plastic polymers. The results suggest that oysters and mussels will not ingest all microplastics that they are exposed to in the natural environment!



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Kayla changing water and replenishing food for the animals.

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An oyster being exposed to microplastics in the laboratory. Microplastics are gently pipetted over the inhalant aperture (where oysters draw particles in) which allows the oysters to choose between drawing the particles in or not (Photo: Kayla Mladinich).

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Mladinich et al. ES&T (2022) Graphical abstract