[P004] Poster

1:00 PM - 1:50 PM JST(4:00 AM - 4:50 AM UTC)

[P02-198] Enhancement of Thermal Stability and Enzymatic Activity of PETase through Cyclization for Efficient PET Degradation

○Jimin Oh¹, JeongEun Hyeon¹ (1. Sungshin Women's Univ. (Korea))

Keywords:

Poly(ethylene terephthalate),PETase,cyclization,thermal stability

Poly(ethylene terephthalate) (PET) is inexpensive and easy to process, making it one of the most widely used plastics in everyday life across various applications such as packaging materials and textiles. However, due to these advantages, its increasing use has led to a significant accumulation of PET waste, making environmental pollution problems more serious. This accumulation contributes not only to soil and marine contamination but also to secondary issues such as microplastic pollution, posing further risks to ecosystems and human health. To reduce these problems, PET, which is highly resistant to natural degradation, must be efficiently broken down using PETase, an enzyme with high catalytic activity and specificity. We measured the enzymatic activity of PETase by adding it to PET and conducting reactions at four different temperatures: 52℃, 58℃, 64℃, and 70℃. As a result, the enzyme activity at 70℃ was found to be lower than that at 52℃, due to the low thermal stability of PETase, which resulted in slower degradation of PET at higher temperatures. But if PETase has thermal stability, it can have higher activity even at high temperatures. These findings suggest that enhancing the thermal stability of PETase is a critical strategy for improving its enzymatic degradation efficiency, particularly under high–temperature conditions. Therefore, in this study, to overcome the low thermal stability of PETase, which limits the efficient and practical enzymatic degradation of PET, and to prevent protein thermal denaturation, we introduced a specific cyclization system at both the N– and C–termini of the PETase sequence to induce enzyme cyclization. This structural modification is expected to enhance the thermal stability and catalytic performance of PETase. Using the cyclized enzyme developed in this study, both the changes in enzymatic activity across different temperatures and the thermal stability according to storage temperature were evaluated, confirming the enhanced thermal stability of cyclized PETase. By developing cyclized PETase with enhanced thermal stability and improved degradation efficiency, it is expected that the applicability of PET biodegradation in industrial processes will be significantly expanded. In particular, this advancement is expected to enable more efficient high–temperature recycling systems and contribute to the development of sustainable and environmentally friendly plastic waste management technologies.