A mesoporous HOM-5 with a structure of 3D cubic monoliths was synthesized by a method of direct-templating, where tetraethyl orthosilicate (TEOS) and Pluronic P123 were used as precursor and surfactant template, respectively, and the concentration of surfactant templates was very low. Our experiments show that a low hydrolysis rate of TEOS facilitates the fabrication of 3D mesoporous structure. The obtained HOM-5 has a high surface area of 746.5 m 2/g, a large pore volume of 1.3 cm 3/g and a narrow pore size distribution around 7.7 nm. The capacity of immobilization of papain in the HOM-5 is 181 mg/g and the immobilized papain shows high thermal and chemical stability compared to the free papain.