Detection of Amount of Lipase Immobilized on Molecular Sieve Mesoporous Silica SBA-15

Candida rugosa lipase (CRL) was immobilized on molecular sieve mesoporous silica SBA-15 by adsorption method. The concentration and the amount of immobilized enzyme protein were determined by three detection methods for comparison, including single wavelength UV spectrophotometric method, double-wavelength UV spectrophotometric method and bicinchoninic acid method(BCA). It was found that the UV spectrophotometric method was interfered easily by SBA-15, and the single wavelength UV method gave much higher results than those by double-wavelength UV and BCA methods, which were relatively near with each other. In addition, the amounts of immobilized enzyme protein on SBA-15 were also measured by BCA method in the presence of various initial enzyme concentrations. The leakage of immobilized enzyme from SBA-15 into buffer solution was investigated through tracking measurement. The amounts of immobilized enzyme protein on two different molecular sieves mesoporous silica SBA-15, named as LLSD1 and Lu001, were 16.6 mg/g support and 114.2 mg/g support, respectively. The leakage amount of immobilized enzyme protein in buffer solution is only 0.5% of total loading. The results prove that SBA-15 can be a feasible immobilization support for lipase.