Fabrication of robust layered double-hydroxide nanoparticles for α-Amylase immobilization: Enhancing catalytic performance, stability, and prospective sustainable biocatalysis applications

A key component in the creation of sustainable processes is the design of novel biocatalysts that increase the stability and reusability of enzymes by immobilization. This study successfully designed an α-amylase biocatalyst using the co-precipitation approach, based on Zn-Al-layered double-hydroxide (LDH) nanoparticles (NPs). The enzymatic activity of the immobilized α-amylase (LDH/Amy) with a particle size of 255 +/- 36 nm was maintained with a high immobilization yield of 97% and an intermediate loading capacity of about 54.81 mg/g of enzyme/LDH. Zeta potential analysis showed that electrostatic interactions influenced enzyme immobilization on the LDH NPs. LDH/Amy exhibited higher Km and increased Vmax, indicating enhanced catalytic activity. Studies on thermal stability revealed that LDH/Amy was more resistant than the free form. Reduction of the activation energy and enhancement of the half-life (T1/2) revealed improved stability of LDH/Amy. In addition, LDH/Amy maintained 90% of its initial activity following 5 consecutive runs and 97.6% of its initial activity following a 25-day storage period. The findings presented in this study indicate the potential utility of LDH NPs as an ecologically benign, low-cost biocatalyst that can promote α-amylase in the hydrolysis of starch for use in pharmaceutical and industrial processes.