Emerging Trends in Nanotechnology and AI-Driven Valorization of Agro-Industrial Waste in Circular Bioeconomy for Production of Biostimulants.

The global agricultural sector faces the dual challenge of increasing productivity while mitigating environmental impacts caused by synthetic agrochemicals and massive agro-industrial waste. This review examines the transition to "Biostimulants 4.0," a circular economy paradigm driven by the valorization of biomass residues into high-value biological inputs through nanotechnology and Artificial Intelligence (AI). Our analysis highlights that green extraction methods, specifically enzymatic hydrolysis, preserve bioactive integrity and reduce carbon emissions by up to 23.2 times compared to synthetic nitrogen production. Furthermore, waste-derived formulations and nanoscale smart-delivery systems dramatically enhance crop performance; for instance, chitosan nanoparticles can achieve up to a 471% increase in specific growth metrics through sustained-release pathways. To move the industry beyond empirical trial-and-error, the integration of AI-driven predictive models now achieves up to 87% accuracy in forecasting biostimulant efficacy. Finally, we contrast global regulatory frameworks and evaluate the monetization of biostimulant-driven carbon sequestration, capable of generating high-integrity credits priced up to $35 per tonne, as a critical economic pathway to accelerate commercial adoption and incentivize a resilient, decarbonized agricultural system.