Plastic can now self-decompose in a short period! Associate Professor Zhang Geng-Leng from the Institute of Environmental Engineering at National Sun Yat-sen University led a team to develop an innovative preparation method for environmentally friendly plastics. They uniformly distributed enzymes within the structure of Polylactic Acid (PLA) to create environmentally friendly bioplastics capable of self-decomposition under normal conditions. This groundbreaking approach opens new avenues for innovative plastic reduction and sustainable development. The research achievements have gained significant attention, winning the gold award at the 2023 Japan Design, Invention, and Creative Exhibition (JDIE), along with a special award from Romania.

Zhang Geng-Leng explained that compared to traditional plastics produced from fossil raw materials, PLA possesses superior physical, chemical, and mechanical properties. It also has advantages such as biocompatibility and biodegradability, making it one of the most promising biodegradable plastics. The research team combined enzymes (Lipase, Lactobacillus plantarum) with PLA bioplastics, overcoming the limitations of microbial decomposition only under specific conditions. The modified bioplastics can accelerate self-decomposition in a general environment, enhancing the potential for promoting eco-friendly plastics.

Traditional plastics not only deplete Earth's energy resources but also contribute to environmental pollution, making it a pressing global concern. Zhang Geng-Leng emphasized that besides restricting the use of conventional plastics, there is a need to develop materials that can replace traditional plastics. Although PLA can persist in the environment at room temperature, similar to traditional plastics, and requires specific conditions, such as 58 degrees Celsius and reliance on a sufficient population of industrial composting microbes, to exhibit its biodegradable properties, many countries have been hesitant to use PLA. To address this issue, the research team focused on systemically controlling and accelerating the decomposition rate of environmentally friendly bioplastics, proposing an innovative and effective preparation method to increase global acceptance and utilization of eco-friendly plastics.

Zhang Geng-Leng explained that the research team first stirred a special solvent and enzyme solution at room temperature for 2 hours to create PLA films embedding the enzymes. These films were then placed in a 60°C culture box with a rotation speed of 100 rpm, reacting with the enzyme solution. The results showed that compared to PLA films with added enzymes in the reaction solution, PLA samples containing enzymes in solutions of 0.1% and 1.0% exhibited better decomposition efficiency. In a 5.0% enzyme solution, the decomposition reached 74% after 21 days. Scanning Electron Microscope (SEM) analysis also revealed differences in appearance and decomposition between films with added enzymes and PLA films containing enzymes.

"The PLA films containing enzymes retained their decomposition ability after 21 days, proving that enzyme-binding with bioplastics has the potential for more applications in self-decomposition," emphasized Zhang Geng-Leng. PLA combined with enzymes helps reduce greenhouse gas emissions during the manufacturing process of petrochemical polymers. The accelerated self-decomposition in a general environment provides a waste management and environmental protection method aligning with the concept of the United Nations' Sustainable Development Goals (SDGs). The hope is to expand the application scope and range of biodegradable plastics through green chemistry research, eventually replacing traditional plastics while balancing convenience and reducing harm to the Earth's environment.