The amount of plastic waste generated more than doubled in nine years from 156 million tons in 2010 to 353 million tons in 2019. On the other hand, the recycling rate of waste plastic is only around 9%. Most of them are reclaimed (about 50%) or unauthorized dumping (22%). These waste plastics are seriously polluting the environment. It is transformed into microplastics, threatening our health. In addition, greenhouse gases caused by the fossil fuel-based plastic industry amounted to about 1.7 billion tons in 2019, more than twice the annual greenhouse gas generation in Korea.
In particular, the problem of marine pollution caused by waste plastic is serious. Waste plastic accounts for about 80% of marine waste, and it is transformed into microplastics, destroying the marine ecosystem by killing marine life. Marine products contaminated with microplastics threaten human health. The G7 is promoting the 3R (Reduce, Reuse, Recycle) promotion plan, the Marine Plastic Charter, and the 2030 Natural Agreement. Its goal is to use more than 50% of recycled plastic products by 2030 and to increase the recycling and reuse rate of plastic packaging materials to more than 55%.
Scholars are developing various bioplastics to solve problems caused by petroleum-based plastics. These are substances such as PLA, PBAT, and PBS. Wouldn't bioplastics currently on the market cause environmental pollution? Biodegradability is better than petroleum-based plastics, but more research is needed on biodegradability in the ocean. In addition, plastic products that can be produced are very limited and expensive, making it difficult to widely use. In addition, there is a plastic resin called PHA, which is synthesized by microorganisms, which can be completely decomposed in the marine environment and is expected to have little adverse effects on the ecosystem.
Despite these advantages, PHA is not yet widely used in the bioplastic market. Because it is expensive. PLA costs about 2,000 won per kilogram, while PHA costs 5,000 won at a low price and 10,000 won at a high price. Potatoes or vegetable oils are used as raw materials, so they are inevitably expensive.
What about food waste? Isn't it a raw material that you can get for free anywhere? If we produce PHA using food waste as a raw material, wouldn't we be able to make plastic that decomposes on the ground and decomposes in the sea? Wouldn't it be possible to prevent environmental pollution caused by waste plastic and protect human health? Carbon neutrality can also be secured.
Is this possible? Commercialization requires more research, but it is possible. Certain microorganisms can synthesize PHA using organic materials. There is a need for a technology that converts food waste into a form that can be directly used as raw materials by PHA-producing microorganisms through various pretreatment. In addition, post-treatment processes such as palletizing PHA or blending with other resins after PHA synthesis are also required.
If it is possible to produce rotting plastic resin PHA using food waste, it will be a double profit. It can solve the problem of food waste and the problem of environmental pollution caused by waste plastic. I believe that if you go step by step, the day will come when plastic that decays into food waste will be mass-produced at low cost. The government and related industries also need to pay attention to PHA production using food waste.
Writer: Yeyoung Jeon
(Picture from Unsplash)