Novel Feruloyl Esterase for the Degradation of Polyethylene Terephthalate (PET) Screened from the Gut Microbiome of Plastic-Degrading Mealworms (Tenebrio Molitor Larvae)

• Published in: Environmental science & technology Vol. 58; no. 40; pp. 17717 - 17731
• Main Authors: Mamtimin, Tursunay, Ouyang, Xingyu, Wu, Wei-Min, Zhou, Tuoyu, Hou, Xiaoxiao, Khan, Aman, Liu, Pu, Zhao, Yi-Lei, Tang, Hongzhi, Criddle, Craig S., Han, Huawen, Li, Xiangkai
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08.10.2024
• Subjects: Animals; Biodegradation, Environmental; Biological properties; Bioremediation; Bioremediation and Biotechnology; Carboxylic Ester Hydrolases - genetics; Carboxylic Ester Hydrolases - metabolism; Chemical degradation; Degradation; Depolymerization; E coli; Enzymes; Esterase; Ferulic acid; Ferulic acid esterase; Gastrointestinal Microbiome; Genes; Intestinal microflora; Larva; Larvae; Lignocellulose; Microbiomes; Molecular dynamics; Physical properties; Plastics; Plastics - metabolism; Polyethylene terephthalate; Polyethylene Terephthalates - metabolism; Resource recovery; Site-directed mutagenesis; Tenebrio; Tenebrio molitor; polyethylene terephthalate (PET); MD simulation; biodegradation; Tenebrio molitor larvae; feruloyl esterase
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/acs.est.4c01495

Mealworms (Tenebrio molitor) larvae can degrade both plastics and lignocellulose through synergistic biological activities of their gut microbiota because they share similarities in chemical and physical properties. Here, a total of 428 genes encoding lignocellulose-degrading enzymes were screened from the gut microbiome of T. molitor larvae to identify poly­(ethylene terephthalate) (PET)-degrading activities. Five genes were successfully expressed in E. coli, among which a feruloyl esterase-like enzyme named TmFae-PETase demonstrated the highest PET degradation activity, converting PET into MHET (0.7 mgMHETeq ·h–1·mgenzyme –1) and TPA (0.2 mgTPAeq ·h–1·mgenzyme –1) at 50 °C. TmFae-PETase showed a preference for the hydrolysis of ferulic acid methyl ester (MFA) in the presence of both PET and MFA. Site-directed mutagenesis and molecular dynamics simulations of TmFae-PETase revealed similar catalytic mechanisms for both PET and MFA. TmFae-PETase effectively depolymerized commercial PET, making it a promising candidate for application. Additionally, the known PET hydrolases IsPETase, FsC, and LCC also hydrolyzed MFA, indicating a potential origin of PET hydrolytic activity from its lignocellulosic-degrading abilities. This study provides an innovative strategy for screening PET-degrading enzymes identified from lignocellulose degradation-related enzymes within the gut microbiome of plastic-degrading mealworms. This discovery expands the existing pool of plastic-degrading enzymes available for resource recovery and bioremediation applications.