Weldon Michael, Ganguly Sanniv, Euler Christian
Department of Chemical Engineering, University of Waterloo, Canada.
Metab Eng Commun. 2024 Dec 12;20:e00253. doi: 10.1016/j.mec.2024.e00253. eCollection 2025 Jun.
The growing plastics end-of-life crisis threatens ecosystems and human health globally. Microbial plastic degradation and upcycling have emerged as potential solutions to this complex challenge, but their industrial feasibility and limitations thereon have not been fully characterized. In this perspective paper, we review literature describing both plastic degradation and transformation of plastic monomers into value-added products by microbes. We aim to understand the current feasibility of combining these into a single, closed-loop process. Our analysis shows that microbial plastic degradation is currently the rate-limiting step to "closing the loop", with reported rates that are orders of magnitude lower than those of pathways to upcycle plastic degradation products. We further find that neither degradation nor upcycling have been demonstrated at rates sufficiently high to justify industrialization at present. As a potential way to address these limitations, we suggest more investigation into mixotrophic approaches, showing that those which leverage the unique properties of plastic degradation products such as ethylene glycol might improve rates sufficiently to motivate industrial process development.
日益严重的塑料生命周期末端危机在全球范围内威胁着生态系统和人类健康。微生物降解塑料及将其升级回收已成为应对这一复杂挑战的潜在解决方案，但其工业可行性及相关限制尚未得到充分描述。在这篇观点论文中，我们回顾了描述微生物降解塑料以及将塑料单体转化为增值产品的文献。我们旨在了解目前将这两者结合成一个单一闭环过程的可行性。我们的分析表明，微生物降解塑料目前是“闭环”的限速步骤，其报道的速率比将塑料降解产物升级回收的途径低几个数量级。我们进一步发现，目前无论是降解还是升级回收，都未证明其速率高到足以证明工业化的合理性。作为解决这些限制的一种潜在方法，我们建议更多地研究混合营养方法，结果表明，那些利用塑料降解产物（如乙二醇）独特性质的方法可能会充分提高速率，从而推动工业工艺的发展。
