Depolymerization and Assimilation of Poly (Ethylene Terephthalate) By Whole-Cell Bioprocess

Abstract

Now, biofunctionalization of synthetic polymers can be achieved through biocatalysts. Uniquely among the great enzyme, whole-cell biocatalysts provide a promising alternative for bioprocess. The bioprocess of depolymerization and assimilation of polyethylene terephthalate (PET) was investigated with whole-cell from aeromonas as biocatalyst in this investigation. The engineered aeromonas strain, which can grow with PET particle as sole carbon source and major energy, was employed as biocatalysts. The main products, such as terephtalic acid (TA), bis (2-hydroxyethyl terephthalate) (BHET) and benzoic acid (BA), muconic acid (MA), were recognized in whole-cell bioprocess of PET depolymerization. It showed that variation of these products was more complex than that in case of enzyme treatment, for the interaction of solid insoluble substrate, microbe cell and enzymes secreted by cells in this heterogeneous process. The result demonstrated that not only the ester bonds can be cleaved, but also the benzene ring can be decomposed in the process of whole-cell catalysis. And some of the intermediate products, which have inhibiting effect in enzyme catalysis process, can be utilized and further degraded in whole-cell bioprocess. Furthermore, assays by DSC showed that as degradation of PET progressed, crystallinity of PET granular increased by 1.81% due to preferential degradation of amorphous regions.