Reviewed by Sarah KellyOct 29 2025
Lehigh University researchers are partnering with Dow Inc. on a National Science Foundation (NSF)-funded project to investigate how microbes break down modified polysaccharides - viscosifiers widely used in everyday products like shampoos, detergents, and cosmetics.
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When you pump shampoo into your hand, you expect a perfect texture - not too runny, not too thick. That smooth consistency comes from viscosifiers, a class of polymers that help stabilize product ingredients in solution. But what happens to those polymers after they’re rinsed down the drain is still largely a mystery.
Wastewater usually goes to a treatment plant, where the solids are filtered out, and the rest is either broken down by microbes or precipitated as sludge before being tested then released into streams.
Xuanhong Cheng, Professor, Bioengineering and Materials Science and Engineering, P.C. Rossin College of Engineering and Applied Science, Lehigh University
Cheng and her team are working with Dow to study how sewage-digesting microbes interact with and potentially break down these viscosifiers. Their research is supported by a three-year NSF GOALI (Grant Opportunities for Academic Liaison with Industry) award, which funds collaborations between universities and industry partners.
The research will begin by mapping how microbes degrade the polymers. Cheng’s lab will combine different microbial strains with various polymers, then track microbial growth and analyze the chemical byproducts of degradation.
One key question is whether mixed microbial communities can break down the polymers more effectively than single strains.
If a consortium of microbes works better, we could design strategies to mix them selectively, targeting different parts of the polymer for complete degradation.
Xuanhong Cheng, Professor, Bioengineering and Materials Science and Engineering, P.C. Rossin College of Engineering and Applied Science, Lehigh University
The team’s objectives are twofold: to deepen understanding of the chemical processes behind full polymer degradation, which could inform future product design, and to identify microbial mixtures that wastewater treatment plants could use to reduce polymer residues in discharged water.
For Cheng, the project also brings the opportunity to mentor the next generation of researchers - a role she deeply values. This past summer, she worked closely with four undergraduate students who actively contributed to the project and will continue their research through the fall.
“It’s motivating to work with students with a clear passion for this problem, and to teach them the skills to help address it. That’s very rewarding for me,” said Cheng.