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An innovative method for immobilizing sucrose isomerase on ε-poly-l-lysine modified mesoporous TiO2

Wu, Lingtian, Liu, Yi, Chi, Bo, Xu, Zheng, Feng, Xiaohai, Li, Sha, Xu, Hong
Food chemistry 2015 v.187 pp. 182-188
biocatalysts, catalytic activity, enzyme activity, food industry, half life, isomaltulose, methodology, pH, porous media, sucrose, temperature, titanium dioxide
Sucrose isomerase (SIase) is the key enzyme in the enzymatic synthesis of isomaltulose. Mesoporous titanium dioxide (M-TiO2) and ε-poly-l-lysine-functionalized M-TiO2 (EPL-M-TiO2) were prepared as carriers for immobilizing SIase. SIase was effectively immobilized on EPL-M-TiO2 (SI-EPL-M-TiO2) with an enzyme activity of 39.41U/g, and the enzymatic activity recovery rate up to 93.26%. The optimal pH and temperature of immobilized SIase were 6.0 and 30°C, respectively. SI-EPL-M-TiO2 was more stable in pH and thermal tests than SIase immobilized on M-TiO2 and free SIase. Km of SI-EPL-M-TiO2 was 204.92mmol/L, and vmax was 45.7μmol/L/s. Batch catalysis reaction of sucrose by SI-EPL-M-TiO2 was performed under the optimal conditions. The half-life period of SI-EPL-M-TiO2 under continuous reaction was 114h, and the conversion rate of sucrose after 16 batches consistently remained at around 95%, which indicates that SI-EPL-M-TiO2 has good operational stability. Thus, SI-EPL-M-TiO2 can be used as a biocatalyst in food industries.