Tian Chi, Wang Yuancheng, Yuan Dihua, Li Yanglin, Tang Xinyu, Chen Yinlin, Luo Tinghao, Shen Guanwang, Zhao Ping, Xia Qingyou
Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, People's Republic of China.
Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Biological Science Research Center, Southwest University, Chongqing 400715, People's Republic of China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing 400715, People's Republic of China.
J Hazard Mater. 2025 Sep 15;496:139446. doi: 10.1016/j.jhazmat.2025.139446. Epub 2025 Aug 5.
Polyethylene terephthalate (PET) is a widely used plastic whose poor degradability has led to serious environmental pollution. In recent years, it was shown that the engineered enzyme FAST-PETase can efficiently catalyze the hydrolysis of PET into monomers; however, large-scale production and low-cost application of this enzyme remain challenging. In this study, we successfully produced FAST-PETase at a large scale using the silk gland expression system of Bombyx mori and integrated an optimized FAST-PETase gene into the B. mori genome using genetic engineering technology. The content of recombinant FAST-PETase reached 53.3 mg per gram of cocoon weight, and approximately 22 % of which can be extracted using mild extraction conditions. The analysis revealed that rFAST-PETase, when extracted from cocoon crude extracts, efficiently and completely hydrolyzes PET plastics into terephthalic acid (TPA) and ethylene glycol (EG). Notably, the extraction method did not affect the spinning properties of the silk. Furthermore, a unique N-glycosylation modification of rFAST-PETase in the silkworm system was identified, which led to a significant enhancement in its thermostability. In comparison with conventional hydrolysis strategies for PET plastics, the cost of the proposed method is reduced by a minimum of 72 %, and the TPA hydrolysis product with 99 % purity can be recycled through an acid precipitation method. These findings indicate that this genetically engineered silk material has potential for use in PET plastic waste recycling.
聚对苯二甲酸乙二酯（PET）是一种广泛使用的塑料，其降解性差导致了严重的环境污染。近年来，研究表明工程酶FAST-PETase能有效催化PET水解成单体；然而，这种酶的大规模生产和低成本应用仍然具有挑战性。在本研究中，我们利用家蚕的丝腺表达系统成功大规模生产了FAST-PETase，并通过基因工程技术将优化的FAST-PETase基因整合到家蚕基因组中。重组FAST-PETase的含量达到每克茧重53.3毫克，其中约22%可在温和的提取条件下提取。分析表明，从茧粗提物中提取的rFAST-PETase能高效且完全地将PET塑料水解为对苯二甲酸（TPA）和乙二醇（EG）。值得注意的是，提取方法不影响蚕丝的纺丝性能。此外，还鉴定出了家蚕系统中rFAST-PETase独特的N-糖基化修饰，这使其热稳定性显著提高。与传统的PET塑料水解策略相比，该方法的成本至少降低了72%，且纯度为99%的TPA水解产物可通过酸沉淀法回收利用。这些发现表明，这种基因工程蚕丝材料在PET塑料废物回收利用方面具有潜在应用价值。
