Turning food waste into biodegradable bioplastics
Researchers in the Virginia Tech College of Agriculture and Life Sciences received a $2.4 million USDA grant to create affordable bioplastics and reduce plastic waste remaining both on land and in the sea.
Zhiwu (Drew) Wang and Ph.D. student Xueyao (Kira) Zhang in Wang's lab located in the Human and Agricultural Biosciences Building I, where the applied research on bioplastics is conducted. Photo by Max Esterhuizen for Virginia Tech.
Researchers in the College of Agriculture and Life Sciences at Virginia Tech received a $2.4 million grant from the U.S. Department of Agriculture (USDA) to create bioplastics from food waste diverted from landfills.
The three-year grant will test the scalability and feasibility of the conversion of these wastes into bioplastics on a national and global scale, with the target of keeping costs for the produced bioplastics as low as possible. Unlike traditional plastics made from petroleum-based materials, bioplastics are made from biological elements such as plant or animal oils and naturally degrade in compost and waterways.
Nearly 40 percent of food produced in the United States ends up in landfills, accounting for the single largest component of municipal waste in the country. This results in not only greenhouse gas emissions, but also carries an annual $165 billion in economic loss from the food, water, energy, and chemicals spent in the food supply chain.
The project also tackles the challenge of oceanic plastic pollution that is becoming ever more apparent, with microplastics affecting nearly 88 percent of all marine species, according to the World Wildlife Fund. Because they can quickly biodegradable in water, these plastics will reduce the lasting impact on marine life across the globe.
The first-of-its kind pilot project will develop and demonstrate an affordable modular bioprocessing system to produce biodegradable bioplastics from food waste.
"This pilot project is a watershed moment in the production of plastics," said Zhiwu "Drew" Wang, the principal investigator, an assistant professor in the Department of Biological Systems Engineering, and director of the Center for Applied Water Research and Innovation. "We will provide a blueprint of how to mass produce biological plastics."
Wang and Zhang operate the ceiling crane in Wang's lab. Photo by Max Esterhuizen for Virginia Tech.
The outcome of this three-year project will be a process that delivers marketable bioplastic products made from food waste. The reusability of food waste for bio-based plastic production could help reduce landfill quantity and waste management costs, offset petroleum-based plastic production and pollution, and minimize greenhouse gas emissions.
"We want to make these environmentally sustainable plastics to be of value to people, to companies, to waste management, and to communities around the globe," said Wang, whose department is part of the College of Agriculture and Life Sciences and the College of Engineering.
Traditional plastics are made from petroleum-based oil. Following that same principle, bioplastic can be made from biological oil, such as animal fat, plant-based oils, or microbial “fat.”
The researchers are using microorganisms to consume food waste, which will in turn allow the microorganisms to grow fats – or biological oils. After the microorganisms have sufficient fats, their cells are opened and the fat is released. After the fat has been purified, it can be processed into bioplastics.
Wang is working in conjunction with other faculty across campus, including Haibo Huang, an associate professor in the Department of Food Science and Technology, and Young Kim, an associate professor in packaging systems and design housed in the Department of Sustainable Biomaterials in the College of Natural Resources and Environment.
The outcome of the research will be high-value bioplastic products, such as bottles, packaging films, and PHA-coated paperboards for single use packaging products. Photo by Max Esterhuizen for Virginia Tech.
Huang’s team focuses on the separation and purification of polyhydroxyalkanoates (PHA), the polymeric fats produced through the fermentation of food waste by the microbial cells.
Kim focuses on using the purified PHAs to manufacture high-value bioplastic products, such as home compostable rigid and flexible packaging systems including bottles, packaging films, and PHA-coated paperboards for single use packaging products, which are in high demand due to the pandemic.
The fermentation process used by the researchers involves something similar to a sight seen in microbreweries – large fermentation vats. After a waste collection company delivers the food waste, it is categorically separated based on food composition, so specific microorganisms can break down the specific types of food wastes. Once the food is broken down, the bacterial cells are split open and the fats are captured, purified, and turned into the plastic products society uses daily.
Wang said this project is exactly why he joined Virginia Tech and the College of Agriculture and Life Sciences – to have a lasting and meaningful impact through applied research.
"I want to focus my research on areas that can quickly translate lab results into industrial application," Wang said. "I want to solve real-world problems and produce things that are useful to communities and to industry. I’m excited to see the effects of this highly applied research in the future."
