Advances in polyurethane biodegradation integrating chemistry, microbial mechanism, and computational approaches

A condensation reaction between an isocyanate and polyols produces a synthetic polymer, polyurethane (PU). Owing to its complex chemical framework, PU is highly recalcitrant. This plastic type consists of hard and soft segments in its structure, which critically influence its mechanical properties and functional versatility. Its inherent structural complexity and resistance to degradation have created significant challenges in its end-of-life management, contributing to persistent plastic pollution. In recent years, microbial-mediated enzymatic degradation has emerged as a promising alternative to conventional waste treatment and disposal strategies. This review provides a comprehensive overview of PU biodegradation, outlining the polymer's chemistry, the role of microbial communities and their associated enzymes, and emerging insights from metabolic pathway analysis to molecular-based metagenomic studies. Standardized testing methods and analytical techniques are evaluated along with physicochemical and environmental factors that influence degradation. Recent innovations like the development of engineered microbial consortia, enzyme optimization strategies, pre-treatment methods, and bio-based formulations collectively advance PU biodegradation and support sustainable material valorisation. In silico approaches, such as machine learning and computational studies, are highlighted for their potential to predict degradation efficiency and guide experimental design. By integrating insights from polymer science, microbial ecology, and computational biology, this review identifies critical challenges and outlines future directions towards developing scalable, eco-efficient solutions for PU waste management and circular material recovery.