Smart nanobiocatalysts for waste-to-biofuel conversion: integrating Nano-Bio interfaces and AI-driven design

Converting diverse waste streams, including agricultural residues, food waste, and industrial by-products, into biofuels is a major challenge for a circular bioeconomy. Smart green nanobiocatalysts are emerging as next-generation tools for sustainable waste-to-biofuel conversion. They combine enzyme specificity with the tunable properties of nanomaterials within circular biorefinery systems. Significant progress has been made in nano-bio interface engineering, AI-assisted catalyst discovery, and circular biorefinery frameworks. However, a comprehensive overview integrating these fields for rational biocatalyst design is still lacking. This review addresses this gap by providing a forward-looking synthesis of nano-bio interface engineering, stimuli-responsive catalytic systems, hybrid nanozyme-enzyme architectures, and AI-assisted catalyst design strategies to improve biochemical conversion and waste valorization. Emphasis is placed on structure-function relationships controlling enzyme immobilization, interfacial electron transfer, and multi-enzyme cascade organization. These features enhance catalytic efficiency, stability, and recyclability under industrial conditions. Applications include waste-derived lignocellulosic biomass, biodiesel feedstocks, food waste, wastewater streams, and anaerobic digestion. Additionally, techno-economic feasibility, life-cycle sustainability, carbon mitigation, and environmental safety are also evaluated. Overall, smart nanobiocatalysts provide a promising pathway toward efficient, climate-friendly, and digitally optimized biofuel production. They support sustainable waste management, resource recovery, and global net-zero energy goals, aligning biofuel innovation with circular bioeconomy objectives.