Biotechnological Application of Surface Modified Cerium Oxide Nanoparticles

Abstract

Re-engineering of chemical materials at the nanoscale level that employ modification and improvement in their physical and chemical properties has been constantly pursued for application in biomedical and biotechnology industries. Moreover, immobilization of catalysts on these bio/chemically modified nanomaterials improved the performance of enzymes in a plethora of industrial uses. Hence, in this study, cerium oxide nanoparticles (CNPs) were synthesized and their morphology was investigated by TEM and UV-spectra. They were modified by carboxylation and glutaraldehyde to achieve highly efficient surface functionalized nanomatrices for immobilizing Aspergillus oryzae β-galactosidase for producing lactose-free products in dairy industries. Enzyme activity for soluble and immobilized enzyme was observed in different pH and temperature ranges, and on galactose mediated competitive inhibition offered by the substrate. It was observed that all the enzyme preparations exhibited temperature-optima at 50 °C and pH-optima at pH 4.5, respectively. Michaelis-Menten K m (mmole/L) values were 2.40, 5.88, 6.02 and 6.11 for soluble β-galactosidase, and enzyme immobilized on CNPs, carboxylated CNPs and glutaraldehyde modified CNPs, respectively. However, V max (mmole/L/min) was found to be 518, 507, 495 and 480 for these enzyme preparations under identical conditions. Immobilized enzyme demonstrated excellent reusability even after seven repeat uses. The bioconversion rates of lactose from solution in continuous batch reactors revealed the remarkable catalytic efficiency of β-galactosidase immobilized on glutaraldehyde modified CNPs in comparison to other enzyme preparations.

Validation and Optimization of Polyvinyl Alcohol-Functionalized Gold Nanoparticles for Producing Lactose-Free Dairy Products

“…The results obtained above are explained by the fact that the conversion of whey lactose is subjected to the enzyme activity which is based on optimum conditions of β-galactosidase like temperature and pH, and also on the processing time and enzyme concentration. 21,29 The present study demonstrated the excellent application of β-galactosidase conjugated to PVA-AuNPs in lactose conversion at 50 o C, owing to its profound thermal stability at this temperature. The fact that β-galactosidases from plant and fungal sources possess acidic pH-optima was discussed in detail.…”

“…Aliquots were collected after a gap of 1 h to monitor the lactose hydrolysis by glucose oxidase-peroxidase assay kit. 21…”

Stabilization of β-Galactosidase on Modified Gold Nanoparticles: A Preliminary Biochemical Study to Obtain Lactose-Free Dairy Products for Lactose-Intolerant Individuals

“…Enzyme engineering through immobilization on surface-modified nanomatrices via multi-subunit covalent binding, entrapment, and adsorption is a preferred approach for improving enzyme properties, such as inhibition by reaction products, activity, specificity, and stability [ 38 ]. The consequent reuse of β-galactosidase bound to PVA-modified AuNPs is shown in Figure 8 .…”

Future Clinical Application of β-galactosidase Stabilized by Magnesium oxide Nanoparticles

“…Activity of β-galactosidase through galactose significantly affects the hydrolysis of lactose, and this challenge can be reflected positively by immobilizing enzyme on MgO-NPs as it counters the activity of β-galactosidase as a protector of the active site access by the galactose [22][23][24][25] . Fig.…”