Plastic waste is a plague that afflicts everyone inhabiting our planet and pollutes our rivers, lakes, and oceans. This problem arises from the lack of reusability of plastic waste, which inadvertently leads to it being dumped into waterways, where microplastics contaminate drinking water.
However, scientists at Southern Illinois University (SIU) discovered a method in which plastic waste can be reduced and even reused into edible protein cookies that could feed humans across the globe. This opens up the possibility of sustaining life in high-stakes environments such as undersea missions or even missions that extend beyond our atmosphere and into deep space.
But what is this miracle cure for plastic waste? The team at SIU began experimenting with microbes aimed at converting polyethylene terephthalate (PET), a common plastic compound found in soda and water bottles. Associate Professor Lahiru Jayakody and graduate student Sandhya Jayasekara focused their research on yeast, during which they bioengineered several varieties of yeast, including baker’s yeast, to break down this waste into proteins, vitamins, and other more useful products.
Although this type of work could be done by chemical reactions in the laboratory, microbes accomplish this task naturally and are significantly more eco-friendly. Jayakody notes that “microbes are very clever. So, we are using their traits to solve the problems we created.”
The yeast cannot immediately break down these materials, so the team first turns these pieces into a more manageable size through a process called oxidative hydrothermal dissolution (OHD). Developed by Ken Anderson, a geology professor at SIU, OHD is a chemical process that only necessitates oxygen, water, and heat. Specifically, the main benefit of this process is that it breaks down resistant materials into minuscule pieces so that the yeast can more effectively break them down. Additionally, this process is cited to be “non-toxic, easily transportable, and amenable to a wide variety of microorganisms,” opening up the possibility of large-scale mass production later in the future.
Once the yeast have produced the necessary ingredients, the researchers subsequently combine them with fiber, starch, and sweetener, then 3D-print nutrient-packed cookies dubbed “μBites.” Although these μBites have been tested for food safety based on available data, researchers are awaiting formal approval before conducting taste tests.
Another benefit of the yeast microbes is their capability to produce additional ingredients derived from plant biomass, such as vanilla and beta-carotene. The researchers’ ultimate goal for this project is to produce a wide variety of ingredients that are needed for μBites and, more broadly, prepare these cookies for public consumption relatively soon.
As global starvation becomes more and more of an overlooked threat, this project offers an innovative solution to this problem while also recycling the waste that threatens our ecosystem into something far more productive.
