Abstract

This mini-review discusses the latest developments in microbial upcycling of PET wastes into high-value products. PET is one of the major types of synthetic plastics that include PE, PP, PS and PVC. PET finds widespread use in making water, soda and beverage bottles and diverse food packaging materials; more than 82 million tons of PET wastes are generated globally per year. PET is highly recalcitrant and massive amounts of PET wastes especially water bottles accumulate and contaminate the environmental sectors including soil, freshwater, and marine ecosystems. Urgent initiatives are, therefore, warranted for safe disposal, recycling and upcycling of PET wastes. Of late, several reports have demonstrated successful upcycling of PET wastes into value-added products such as adipic acid, gluconic acid, lycopene, paracetamol, and vanillin etc. Microbial bio-upcycling integrates chemical or enzymatic pretreatment of PET wastes with microbial conversion of the building blocks into high-value end-products via natural or engineered microbes e.g. E. coli, Gluconobacter oxydans, Ideonellasakaiensis, Pseudomonas putida, and Rhodococcus jostii etc. Further research efforts must now be directed towards scaling up of the production of highvalue chemicals at commercial scale from PET wastes, exploring the feasibility of similar upcycling processes for other plastic wastes, and ushering a circular, secure, and sustainable economy of synthetic plastics without further depletion of fossil fuel reserves; continued aggravation of climate change; and further deterioration of Earth’s ecosystems.

Keywords

polyethylene terephthalate, upcycling, adipic acid, vanillin, paracetamol, lycopene, ideonella sakaiensis, engineered microbes, circular economy