Cellulose-gold nanohybrid as an effective support to enhance the catalytic efficiency and stability of α-amylase from Bacillus aquimaris

Cellulose nanocrystals/gold nanoparticle hybrids were synthesized under extreme conditions using hydrothermal treatment without utilizing toxic chemicals. The synthesis of the designed nanohybrid and enzyme immobilization process were confirmed by FT-IR, DLS, intrinsic fluorescence, UV-Vis spectroscopy, FESEM, and EDX techniques. The enzyme, in its free form, exhibited maximum activity at a pH of 10 and a temperature of 70 degrees C. However, when the enzyme was immobilized, its optimal temperature increased to 80 degrees C while its optimal pH remained constant. This catalytic platform significantly improved the thermal and chemical stability, along with enzyme stability at significant pH levels. Following a storage period of four weeks, it was observed that immobilized alpha-amylase retained 67.5 % of its initial activity, while free alpha-amylase retained only 17 % of its initial activity. The immobilized alpha-amylase exhibited a catalytic efficiency of 0.488 mM(-1) s(-1), which was found to be twice as high as that of the free form, which had a catalytic efficiency of 0.254 mM(-1) s(-1). The immobilized enzyme retained its initial activity up to 75 % after 11 consecutive uses. On the basis of the obtained results, it appears that the manufactured immobilized enzyme represents an appropriate choice for industrial use under harsh conditions.

Automated summary

Cellulose nanocrystals/gold nanoparticle hybrids were synthesized using hydrothermal treatment without toxic chemicals. The immobilized enzyme showed increased optimal temperature and retained higher activity and efficiency under extreme conditions.