Xiangmin Liang, Making Bioplastic from Microorganisms in Wastewater Sludge

Did you know that microbiologists and engineers have been working for several years to harvest plastics from bacteria in wastewater sludge? Now Xiangmin Liang, a UD Ph.D. student and DENIN Environmental Fellow, is trying to make the plastics stronger.

Liang, in cooperation with Daniel Cha, professor of civil and environmental engineering,feeds large amounts of organic materials to bacteria in wastewater, and the bacteria store energy as polymers that we can use to make a plastic matrix. Liang is experimenting with using other bacteria to reinforce the plastic matrix.

By combining the matrix and the reinforcement, he can make plastics withproperties suitable for widespread use in consumer products and industry.These plasticsare environmentally friendly, renewable, sustainable, and economical.They can be used to make furniture or construction materials—“just like stuff you can buy at Home Depot,” says Liang.

The material could serve as an alternative to petroleum-based plastic. “If our ideas come true,” Liang says, “we will decrease petroleum consumption, because a lot of plastic products come from the petroleum industry now. We could save money or even make a profit from the wastewater treatment industry.”

Liang earned a bachelor’s degree in water supply and sewerage science and engineering from Huazhong University of Scienceand Technology in China, then came to the Illinois Institute of Technology in Chicago for his master’s degree in environmental engineering. His advisor there recommended the environmental engineering program at UD. A professor from his alma mater in China who was a visiting scholar at UD concurred, so he enrolled.

Liang is now about halfway through this Ph.D. When he finishes in 2 or 3 years, he hopes to continue conducting research in academia. His goal is to become a professor and teach students devoted to environmental protection through engineering.

by Joy Drohan, Eco-Write, LLC

Photo: Liang measures the ammonia concentration in his biological reactor. Credit: Inyoung Kim