INFLUENCE OF pH AND TEMPERATURE ON THE ACTIVITY OF SnO₂-BOUND α-AMYLASE: A GENOTOXICITY ASSESSMENT OF SnO₂ NANOPARTICLES

Abstract

Immobilization of biologically important molecules on a myriad of nanosized materials has attracted great attention due to their small size, biocompatibility, higher surface-to-volume ratio, and lower toxicity. These properties make nanoparticles (NPs) a superior matrix over bulk material for the immobilization of enzymes and proteins. In the present study, Bacillus amyloliquefaciens α-amylase was immobilized on SnO₂ nanoparticles by a simple adsorption mechanism. Nanoparticle-adsorbed enzyme retained 90% of the original enzyme activity. Thermal stability of nanosupport was investigated by thermogravimetric and differential thermal analysis. Scanning electron microscopic studies showed that NPs have porous structure for the high-yield immobilization of α-amylase. The genotoxicity of SnO₂-NPs was analyzed by pUC¹⁹ plasmid nicking and comet assay and revealed that no remarkable DNA damage occurred in lymphocytes. The pH-optima was found to be the same for both free and SnO₂-NPs bound enzyme, while the temperature-optimum for NPs-adsorbed α-amylase was 5°C higher than its free counterpart. Immobilized enzyme retained more than 70% enzyme activity even after its eight repeated uses.

Keywords:

• α-amylase
• genotoxicity
• immobilization
• SnO₂-NPs
• starch hydrolysis

ACKNOWLEDGMENTS

The authors gratefully acknowledge EM Central Facility, Textile Technology Department, IIT Delhi, India, for SEM analysis. The authors are also thankful to the University Grants Commission, New Delhi, India, for sponsoring a fellowship to one of us (M. J. Khan).

Notes

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