This study presents that covalent immobilization technique has been utilized for the immobilization of L-Lactate dehydrogenase (L-LDH) from porcine on mesoporous silica. To develop mesoporous silica as support material for use in L-LDH immobilization, where the particle surfaces were functionalized with 3-aminopropyltrimethoxysilane (APTES) and further conjugated with glutaraldehyde. The effect of some parameters such as glutaraldehyde concentration, immobilization pH, initial enzyme concentration and immobilization time was investigated and the optimum conditions for these parameters were determined as 1% (w/v), pH 8.0, 1 mg/mL and 120 min, respectively. The maximum working pH and temperature for the oxidation of lactate to pyruvate reaction were determined as 10.0 and 35 °C for free and 9.0 and 40 °C for immobilized L-LDH, respectively. The kinetic parameters (Km and Vmax) of L-LDH for the oxidation of lactate to pyruvate reaction were examined as 1.02 mM and 7.58 U/mg prot. for free and 0.635 mM and 1.7 U/mg prot. for immobilized L-LDH, respectively. Moreover, the immobilized L-LDH was 1.3-fold more stable than free L-LDH at 25 °C according to calculated t1/2 values. The immobilized L-LDH retained 80% of its initial activity in a batch reactor after 14 reuses.

Lactate dehydrogenase from porcine (L-LDH) was immobilized on modified mesoporous silica Free and immobilized L-LDH samples were characterized by using SEM and FTIR. After the immobilization process, Immobilized L-LDH had higher thermal stability than that of free L-LDH

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