Constructing Innovative Engineered Enzyme Biocatalysts for Treatment of Emerging Environmental Contaminants

The rapid progresses in industrialization and urbanization of human society have always been accompanied with a wealth of environmental issues. Environmental pollution is essentially one of the most enormous challenges that people have ever encountered because it is closely related to the well beings of the entire ecosystems and humans on the planet. In recent years, the increasing production and usage of newly designed synthetic chemical compounds lead to their release and presence in various engineered and natural environmental components as emerging contaminants (ECs) which would potentially pose considerable health and ecological risks. Biocatalysis is regarded as a green chemistry technique for environmental remediation because of its low consumption of energy input and costly chemical reagent use as well as minimal generation of unknown byproducts. However, it is not appropriate to use free enzymes in practical scenarios due to their short lifetimes, non-reusability, and laborious enzyme purification processes. Meanwhile, although traditional protein immobilization methods, like entrapment, encapsulation, and cross-linking, could improve the catalytic performance of enzymes, they still suffer from numbers of weaknesses, including the loss of enzyme activity during the immobilization processes, multiple and complicated immobilization steps, and mass transfer limitations. Therefore, implementation of new enzyme immobilization strategies to develop robust and efficient biocatalysts for contaminant treatment purposes is particularly needed. In order to address the aforementioned challenges, the primary focus of my Ph.D. study is to engineer yeast and bacterial microbial systems using advanced molecular biology and synthetic biology techniques to develop innovative enzyme biocatalysts for treatment of emerging environmental contaminants. Generally, parabens, bisphenols, and polyethylene terephthalate (PET) plastics were used as representative ECs, and a variety of innovative biocatalysts engineered with respective cutinase, tyrosinase, and PETase enzyme were constructed accordingly for biocatalytic degradation of these ECs.