碳水化合物结合模块-嗜热子囊菌角质酶融合蛋白在PET降解中的应用

The application of carbohydrate binding module-Thermobifida fusca cutinase fusion protein in polyethylene terephthalate degradation

摘要:

随着全球经济的发展，聚对苯二甲酸乙二醇酯(PET) 塑料的生产量大幅提高，其废弃总量也逐年递增。废弃PET处理方法主要包括填埋、焚烧及生物降解等。填埋和焚烧均会造成二次污染，而生物降解因其环境友好特性逐渐成为研究热点。相关研究表明，碳水化合物结合模块(carbohydrate binding module, CBM) 可以有效增强PET降解酶对PET的吸附，从而增加降解速率。通过大引物PCR (megaprimer PCR of whole plasmids, MEGAWHOP) 技术，将炭疽杆菌(Bacillus anthraci) 来源的CBM与嗜热子囊菌(Thermobifida fusca) 角质酶(Tfuc) 构建融合蛋白BaCBM2-Tfuc并表征其PET降解性能。在60 ℃条件下，BaCBM2-Tfuc降解PET膜的效率是Tfuc的2.8倍。本研究可为构建高效降解PET的融合蛋白提供技术支持。

关键词:聚对苯二甲酸乙二醇酯;生物降解;角质酶;碳水化合物结合模块;融合蛋白

Abstract:

With the development of global economy, the dramatically increased production of polyethylene terephthalate (PET) plastics has led to a remarkably increased amount of plastic waste. PET waste can be treated by landfill, incineration, or biodegradation. While landfilling and incineration may cause secondary pollution, biodegradation has since received increased attentions due to its environmental friendliness. Recent studies have indicated that the carbohydrate binding module (CBM) can effectively enhance the binding of PET degrading enzymes to PET, and consequently increasing PET degradation rate. Here we constructed a fusion protein BaCBM2-Tfuc containing the BaCBM2 from Bacillus anthraci and the cutinase Tfuc from Thermobifida fusca, by megaprimer PCR of whole plasmids (MEGAWHOP). Notabaly, the PET film degradation efficiency (at 60 ℃) of BaCBM2-Tfuc was 2.8 times that of Tfuc. This study may provide technical support for constructing fusion proteins capable of efficiently degrading PET.

Key words:polyethylene terephthalate;biodegradation;cutinase;carbohydrate-binding module;fusion protein