Cornell Scientists Develop Enzymes to Combat Microplastic Pollution in Waste Water

Microplastics, defined as plastic particles smaller than 5 mm, pose significant risks to human health and agricultural productivity. These pollutants disrupt soil nutrient cycles, impair plant growth, and can enter the food chain through crops and livestock. Wastewater treatment plants are major contributors to this issue, releasing more microplastics into soils annually than into oceans.

Goddard's team is focusing on engineering enzymes specifically designed to break down polyethylene terephthalate (PET), a common plastic used in packaging and textiles. Originally discovered in the bacteria Ideonella sakaiensis near a Japanese landfill in 2016, these enzymes naturally degrade PET. The researchers are adapting them to thrive in the challenging conditions of sewage sludge, which include high temperatures, variable pH levels, and abundant organic matter.

“Our goal is to integrate these enzymes into wastewater treatment processes to reduce microplastics in treated effluent, particularly as treated wastewater is increasingly used for agricultural irrigation amid global water scarcity,” explained Goddard.

The development process involves sophisticated techniques such as genome sequencing, computational analysis to identify critical amino acids, and extensive testing of enzyme variants. The team is also working on a version of the enzyme that can bind to materials used in wastewater filters, facilitating easier recovery and reuse.

This research, inspired by former graduate student Hannah Zurier, Ph.D., now at Columbia University, and continued by doctoral candidate Sonia Su, responds to the urgent need for effective microplastic removal. Recent studies have highlighted significantly higher microplastic levels in bottled water than previously estimated, underscoring the importance of this work. Additionally, the United Nations is currently deliberating an international treaty to combat plastic pollution.

“Given the scarcity of freshwater, it's crucial to remove microplastics from wastewater to ensure its suitability as an alternative resource. This is vital for health, environmental sustainability, and the long-term economic viability of agriculture,” emphasized Goddard.