Bio-Inspired Catalytic Pathways in Green Chemistry: Recent Innovations in Waste Valorization Processes-A Review

The importance of catalysis in the development of waste management systems in the circular economy is undeniable. This review emphasizes the emerging potential of nature-based bio-inspired catalysis to advance waste valorization. It discusses the potential of bio-inspired catalysis for waste valorization over the last 5 years. In this context, we examine the potential of four methods to utilize waste streams: enzymes, biomimetic enzyme mimics, microorganisms, and hybrid nano-bio systems. Beyond summarizing recent developments, this review provides an integrative and critical framework that connects waste-stream characteristics, catalytic platform selection, target products, and green-chemistry performance criteria. Enzymes are a unique class of catalysts that enable the degradation of plastic waste and lignocellulosic waste, and operate under mild conditions. Biomimetic catalysts such as porous coordination polymers, metal-organic frameworks, nanozymes, and others provide stability, thereby expanding the scope of catalyst use in enzymatic reactions, including CO₂ conversion, terpene epoxidation, and other reactions. Microbial and consortia systems convert complex dilute feedstocks into liquid fuels, acids, or bioplastics, whereas bioelectrochemical systems integrate waste-to-energy remediation. The greatest improvement is achieved with hybrid nano-bio catalytic systems, which provide the greatest stability for enzymes and the greatest enhancement of electrochemical processes (electron transfer) by immobilizing enzymes onto either carbon supports or photoactive supports. All of the aforementioned systems and methods restore the environment by producing useful products through the treatment, purification, and recycling of waste streams. Based on the principles of green chemistry, this review evaluates the scope and limitations and highlights key challenges to focus on the more promising advances among the methods provided. Rather than treating enzymatic, biomimetic, microbial, and hybrid nano-bio systems as isolated categories, this review compares them within a unified framework that identifies their complementary roles, trade-offs, and opportunities for integration across different waste streams and valorization targets.