Improvement of lactulose synthesis through optimization of reaction conditions with immobilized β-galactosidase

摘要: Kluyveromyces lactis β-galactosidase was immobilized on silica gels using a covalent bonding method. To improve lactulose synthesis β-galactosidase, the optimal reaction conditions, such as lactose and fructose concentrations, pH ionic strength of buffer, loading amount enzyme temperature, were determined. Lactulose markedly improved after optimization conditions. When carried out at 47 °C 40% (w/v) lactose, 20% 12 U/ml in 50 mM sodium phosphate buffer 7.5, concentration specific productivity 15.80 g/l 1.32 mg/U·h, respectively. In addition, when reused for synthesis, its catalytic activity retained 60.5% 10 reuses.