<p>Starch hydrolysis and the reduction of nitroaromatic compounds are crucial for various industrial and environmental applications, highlighting the need for the development of catalytic systems that offer high efficiency, rapid reaction kinetics, and sustainability. Nanoclusters stabilized by biological ligands have emerged as promising candidates due to their ultra-small size, large surface area, and eco-friendly characteristics, making them suitable for catalytic applications. This study focuses on synthesis and characterization of organic solvent-free copper nanoclusters (CuNCs) capped with α-amylase, a bio-origin enzyme extracted from the porcine pancreas. The synthesized α-amylase-CuNCs are stable, exhibit blue fluorescence, and have an average cluster size of approximately 2.3 nm, as confirmed by transmission electron microscopy (TEM) analysis. These nanoclusters demonstrate dual catalytic capabilities, facilitating both enhanced starch hydrolysis and the efficient reduction of toxic nitroaromatic pollutants. While α-amylase is inherently capable of catalyzing starch hydrolysis, its combination with copper in these nanoclusters enhances enzymatic performance, suggesting a synergistic effect. This is supported by Michaelis–Menten kinetics analysis, where V_max value of α-amylase-CuNCs (2.61 ± 0.017 μM min⁻¹) is approximately 2.5 times higher than that of α-amylase alone (1.07 ± 0.031 μM min⁻¹), along with a lower K_m values for α-amylase-CuNCs. Additionally, the CuNCs enable the rapid reduction of nitroaniline and nitrophenol within 10 min, achieving conversion yields exceeding 90%, outperforming many previously reported nanoparticle and nanocluster-based catalysts. The water-solubility, stability, and bio-derived nature of the α-amylase-CuNCs make them promising eco-friendly catalysts for starch hydrolysis and the detoxification of nitroaromatic pollutants.</p> Graphical abstract <p></p>