Enzymatic Degradation of Polyethylene Terephthalate Plastics by Bacterial Curli Display PETase

Abstract

The extensive production and use of polyethylene terephthalate (PET) have generated an enormous amount of plastic waste, which potentially threatens the environment and humans. Enzyme biocatalysis is a promising green chemistry alternative, relative to the conventional fossil-derived production process, to achieve plastic waste treatment and recycling. In this work, we created a biocatalyst, BIND-PETase, by genetically engineering the curli of an Escherichia coli cell with a functional PETase enzyme for biocatalytic degradation of PET plastics. BIND-PETase could degrade PET to generate degradation products at the concentration level of greater than 3000 μM under various reaction conditions. The effects of key reaction parameters, including pH, temperature, plastic substrate mass load, and surfactant addition were characterized. BIND-PETase was reusable for PET degradation and remained stable with no significant enzyme activity loss when stored at both 4 °C and room temperature for 30 days (Student’s t test, p > 0.05). Notably, BIND-PETase could enable the degradation of PET microplastics in wastewater effluent matrix. Moreover, BIND-PETase could depolymerize highly crystalline postconsumer PET waste materials under ambient conditions with degradation efficiency of 9.1% in 7 days. This study provides a new horizon for developing environmentally friendly biocatalytic approaches to solve the plastic degradation and recycling challenge.

Synthesis of Metal–Organic Frameworks through Enzymatically Recycled Polyethylene Terephthalate

“…MHET can be further hydrolyzed by MHET hydrolase (MHETase) into TPA and EG to enhance the TPA concentration . After the MHETase treatment, most of the MHET was converted and the bac-TPA and enz-TPA reached 2.5 mM and 6.2 mM, respectively, which is similar to reported studies. ,, Though the purified enzymes and cell lysate originate from the same volume of cell culture, the purification process facilitates the concentration of the enzymes. In contrast, the cell lysate ultimately maintains a volume that is 10-fold greater than that of the purified enzyme, attributable to the ample volume of lysis buffer required to ensure comprehensive cell lysis during sonication.…”

Call for biotechnological approach to degrade plastic in the era of COVID-19 pandemic

“…Under a wide range of reaction conditions, BIND-PETase can depolymerize 9.1% of highly crystalline post-consumer PET waste in 7 days at room temperature and humidity. This study's results provide the crucial groundwork for designing eco-friendly biocatalytic strategies for plastic degradation and recycling ( Zhu et al, 2022 ).…”

Biocatalysis: landmark discoveries and applications in chemical synthesis

“…Biocatalysts have been applied to a diverse range of industrial applications within the pharmaceutical, agricultural, chemical, cosmetic, and food industries (Fig. 4) including; the multi-ton production of the synthetic polymer polyacrylamide using nitrile hydratases, 98 enzyme catalysed biofuel production, 99 enzyme catalysed degradation of plastics, 2,100,101 the industrial production of agrichemicals, such as the herbicide Frontier X2®, 102 and in the biocatalysed production of the important drug intermediate, l -phenylacetylcarbinol ( l -PAC). 103 The food industry applies a range of biocatalysts for additive, catalytic and ingredient requirements in beverage fermentation, baking, meat and dairy processes.…”