UNT professor researches modified organisms
Paul Wedding / Staff Writer
In the midst of heated debates over the potential negative effects genetically modified organisms could have on the environment, one UNT professor is researching a way they could help it.
Associate biology professor Stevens Brumbley has been researching ways to produce biodegradable plastic from genetically modified plants for the past 12 years and is starting to produce it at levels fit for commercial use.
“These are going to feed the new bio economy,” Brumbley said.
Currently, 300 billion metric tons of plastics are generated by the world every year. They are largely nondegradable and end up in landfills, waterways or out in the ocean, and will be there for thousands of years, Brumbley said.
According to the Environmental Protection Agency, the U.S. alone generated almost 14 million tons of plastic waste in 2012, only 9 percent of which was recovered for recycling.
This could end up being a threat to the food chain as well, as the base animals could start consuming them and dying off, causing a disaster throughout the entire chain. About 100,000 marine creatures and 1 million seabirds die per year from plastic entanglement, according to oceancrusaders.org.
Extracting the plastic from the plants begins with an injection of metabolic pathways from bacteria into the embryogenic callus of the plants, which is a mass of plant tissue bombarded with hormones. The genes to convert plants into plastic only exist in bacteria, which is why genetic modification is necessary. The plant is then crushed and carbon dioxide and sugar is extracted from the leaves, which are then converted into bioplastic through fermentation.
The leaf dry weight – the amount of polymer extracted from the plant for bioplastic production – must meet between 7.5 and 15 percent in order to be viable for commercial use. Brumbley has been able to extract at least 6.5 percent from leaves, and some have even hit 12 percent.
Richard McQualter, a post-doctoral researcher who works with Brumbley, has replaced one of the enzymes in the process in order to better capture the materials needed to make bioplastic.
“We were able to double bioplastic production close to commercially viable levels,” McQualter said. “These new plants were actually more healthy than the plants we used previously using the less efficient enzyme.”
They are conducting these tests on sugar cane plants. This is due to its large biomass, as it is the largest plant on Earth. Between 42 and 50 percent of the dry weight of the stalk is sucrose, which can be used to make bioplastic.
Brumbley sees this as a viable alternative to wean the world off its dependence on petroleum, which is used in plastic production. This could be a potential solution to the billions of tons of carbon that are dumped into the ocean every year, he said.
“I don’t expect that we’ll ever stop using petroleum, just that we need to stop using so much” Brumbley said.
McQualter hopes the bioplastic will be able to replace petrochemical plastics. Ideally, bioplastics would be used for drink bottles and coffee pods, which make up a large percentage of landfill, he said.
There are numerous medical uses for bioplastic as well. Scientists have come up with bioabsorbable sutures that have no side effects. They have also created bioabsorbable skin and heart valves. Bioplastic is extremely diverse and able to be used for multiple purposes, Brumbley said.
The bioplastic being produced will only cost between 60 and 80 cents to make, and sold for only one to two dollars per pound, which will be cost competitive with petroleum plastic.
Sugar cane is not the only high biomass crop being tested on. Sorghum, which can produce almost as much biomass, will be used to make bioethanol at a mill in Florida.
“Our method can be transferred over to high-biomass grasses as well as tobacco and poplar, so I’m not the only guy with this brilliant idea,” Brumbley said.
There are currently three biorefineries making bioplastic: two that use wheat and one that uses corn. Brumbley expects that many more will be built.
“Right now Houston and Philadelphia are where our energy comes from,” Brumbley said. “In the future it could be from central Ohio or South Carolina.”
Featured Image: Dr. Stevens Brumbley is an associate professor of biological sciences at UNT. Photo by Devin Dakota – Staff Photographer
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