Huang Tong, Zhang Jingya, Dong Xuena, Yang Yu
School of Life Science, Beijing Institute of Technology, Beijing, China.
Appl Environ Microbiol. 2025 Apr 23;91(4):e0256224. doi: 10.1128/aem.02562-24. Epub 2025 Apr 2.
Identification of novel plastic-degrading enzymes is crucial for developing enzymatic degradation and recycling strategies for plastic waste. Here, we report the discovery of two novel cutinases, SiCut1 and SiCut2, from a yeast strain sp. BIT-D3 was isolated from the gut of plastic-eating mealworms. Their amino acid sequences share less than 25% identity with all previously described cutinases and reveal a conserved S-D-H catalytic triad with a unique GYSKG motif. Their recombinant proteins were successfully overexpressed in . The pH range for both enzymes was 4.0 to 11.0 and the temperature range for SiCut1 and SiCut2 was 10°C to 50°C and 10°C to 70°C, respectively. Both enzymes showed strong activity against apple cutin and short-chain fatty acid esters of -nitrophenol and glycerol, substantiating their classification as true cutinases. SiCut1 and SiCut2 have been demonstrated to exhibit efficient degradation of polycaprolactone (PCL) film, polybutylene succinate (PBS) film, and polyester-polyurethane (PUR) foam. Molecular docking and molecular dynamics simulations were used to elucidate the underlying mechanisms of the observed catalytic activity and thermal stability. This study shows that SiCut1 and SiCut2 are novel yeast-derived cutinases with the potential for depolymerization and recycling of plastic waste.IMPORTANCEThe identification of novel plastic-degrading enzymes is critical in addressing the pervasive problem of plastic pollution. This study presents two unique cutinases, SiCut1 and SiCut2, derived from the yeast sp. BIT-D3 isolated from the gut of plastic-feeding mealworms. Despite sharing less than 25% sequence identity with known cutinases, both enzymes exhibit remarkable degradation capabilities against various polyester plastics, including polycaprolactone (PCL) film, polybutylene succinate (PBS) film, and polyester-polyurethane (PUR) foam. Our results elucidate the catalytic mechanisms of SiCut1 and SiCut2 and provide insights into their potential applications in enzymatic degradation and recycling strategies. By harnessing the gut microbiota of plastic-degrading organisms, this research lays the foundation for innovative enzyme-based solutions to reduce plastic waste and promote sustainable practices in waste management.
鉴定新型塑料降解酶对于开发塑料垃圾的酶促降解和回收策略至关重要。在此，我们报告从一株酵母菌株sp. BIT-D3中发现了两种新型角质酶SiCut1和SiCut2，该酵母菌株是从食塑料黄粉虫的肠道中分离得到的。它们的氨基酸序列与所有先前描述的角质酶的序列同一性低于25%，并揭示了一个保守的S-D-H催化三联体以及一个独特的GYSKG基序。它们的重组蛋白在……中成功实现了过表达。这两种酶的pH范围均为4.0至11.0，SiCut1和SiCut2的温度范围分别为10°C至50°C和10°C至70°C。两种酶对苹果角质以及对硝基苯酚和甘油的短链脂肪酸酯均表现出较强活性，证实它们可归类为真正的角质酶。已证明SiCut1和SiCut2能有效降解聚己内酯（PCL）薄膜、聚丁二酸丁二醇酯（PBS）薄膜和聚酯-聚氨酯（PUR）泡沫。利用分子对接和分子动力学模拟来阐明所观察到的催化活性和热稳定性的潜在机制。本研究表明，SiCut1和SiCut2是新型酵母源角质酶，具有降解和回收塑料垃圾的潜力。重要性鉴定新型塑料降解酶对于解决普遍存在的塑料污染问题至关重要。本研究展示了两种独特的角质酶SiCut1和SiCut2，它们源自从食塑料黄粉虫肠道中分离得到的酵母菌株sp. BIT-D3。尽管与已知角质酶的序列同一性低于25%，但这两种酶对各种聚酯塑料，包括聚己内酯（PCL）薄膜、聚丁二酸丁二醇酯（PBS）薄膜和聚酯-聚氨酯（PUR）泡沫，均表现出显著的降解能力。我们的结果阐明了SiCut1和SiCut2的催化机制，并为它们在酶促降解和回收策略中的潜在应用提供了见解。通过利用塑料降解生物的肠道微生物群，本研究为基于酶的创新解决方案奠定了基础，以减少塑料垃圾并促进废物管理中的可持续实践。
