Immobilization of β-galactosidase from Lactobacillus plantarum HF571129 on ZnO nanoparticles: characterization and lactose hydrolysis.
β-Galactosidase from Lactobacillus plantarum HF571129 was immobilized on zinc oxide nanoparticles (ZnO NPs) using adsorption and cross-linking technique. Immobilized β-galactosidase showed broad-spectrum pH optima at pH 5-7.5 and temperature 50-60 °C. Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) showed that β-galactosidase successfully immobilized onto supports. Due to the limited diffusion of high molecular weight substrate, K m of immobilized enzyme slightly increased from 6.64 to 10.22 mM, while V max increased from 147.5 to 192.4 µmol min(-1) mg(-1) as compared to the soluble enzyme. The cross-linked adsorbed enzyme retained 90 % activity after 1-month storage, while the native enzyme showed only 74 % activity under similar incubation conditions. The cross-linked β-galactosidase showed activity until the seventh cycle and maintained 88.02 % activity even after the third cycle. The activation energy of thermal deactivation from immobilized biocatalyst was 24.33 kcal/mol with a half-life of 130.78 min at 35 °C. The rate of lactose hydrolysis for batch and packed bed was found to be 0.023 and 0.04 min(-1).
School of BioSciences and Technology, VIT University, Vellore, Tamil Nadu, India.
E
E
Selvarajan
V
V
Mohanasrinivasan
C
C
Subathra Devi
C
C
George Priya Doss
D000327:Adsorption; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D006868:Hydrolysis; D048191:Lactiplantibacillus plantarum / Q000145:classification / Q000201:enzymology*; D007785:Lactose / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D013045:Species Specificity; D013379:Substrate Specificity; D015034:Zinc Oxide / Q000737:chemistry*; D001616:beta-Galactosidase / Q000737:chemistry*
D004800:Enzymes, Immobilized; D001616:beta-Galactosidase; D007785:Lactose; D015034:Zinc Oxide