Issue 8, 2025

Tandem chemical hydrolysis and bioelectrochemical upcycling of waste polyethylene terephthalate (PET) for sustainable biobutanol and ethanol production ensuring plastics circularity

Abstract

To establish a sustainable plastic system, it is crucial to implement effective recycling and upcycling strategies that circulate the materials within the market and prevent them from entering the ecosystems. Polyethylene terephthalate (PET), which is the most widely used fossil-derived synthetic polyester, is usually disposed as waste. Development of novel chemical upcycling technologies that can transform plastic wastes into economically viable chemicals is crucial to establish a circular plastics economy. This study delineated a methodology to combine mild chemical pretreatment and biocatalysts via bio-electrofermentation for the conversion of waste PET to sustainable biofuel blendstocks. Initially, PET was depolymerised to its monomers using an alkali catalyst (>98% conversion efficiency), and their structural characteristics were confirmed using FT-IR, NMR (1H and 13C), TGA, FESEM, XRD and XPS techniques. Furthermore, co-culturing with Klebsiella sp. and Clostridium sp. showed positive result towards TPA degradation (55%–74%) with various applied poised potentials to yield high-value bio-fuels. The electrochemical analysis highlighted the role of applied potential in the bioelectrochemical system (BES), where the +0.8 V condition consistently demonstrated a better performance across all metrics, including electron flux, substrate conversion, and product yield. The maximum yield were found to be 0.31 g L−1  for butanol and 0.23 g L−1 for ethanol at +0.8 V in the BES. On the other hand, the life cycle assessment (LCA) methodology was employed to understand the environmental footprints of the studied upcycling process, and it showed a global warming potential of 1.13 ton CO2 eq. per ton biofuel. While, recycling PET accounted for 1.96 ton CO2 eq. and 3.06 ton CO2 eq. from the ideal PET production process. Alternatively, other chemical and enzymatic PET upcycling processes had 3–7 times higher impacts. Therefore, the present work paves a new way for the upcycling of PET and makes a significant contribution to the development of a circular plastics economy.

Graphical abstract: Tandem chemical hydrolysis and bioelectrochemical upcycling of waste polyethylene terephthalate (PET) for sustainable biobutanol and ethanol production ensuring plastics circularity

Supplementary files

Article information

Article type
Paper
Submitted
05 Oct 2024
Accepted
31 Dec 2024
First published
02 Jan 2025

Green Chem., 2025,27, 2359-2373

Tandem chemical hydrolysis and bioelectrochemical upcycling of waste polyethylene terephthalate (PET) for sustainable biobutanol and ethanol production ensuring plastics circularity

H. Kopperi, V. Mamidi, G. Suresh and S. Venkata Mohan, Green Chem., 2025, 27, 2359 DOI: 10.1039/D4GC04985C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements