Selective hydrolysis of fish oil using Rhizomucor miehei lipase immobilized on silica nanoparticles

we report immobilization of Rhizomucor miehei lipase (RML) by random and oriented methods. For thispurpose, silica nanoparticles (SBA-15 and MCM-41) were prepared, characterized and functionalized byglycidyloxypropyle trimethoxysilane (GPTMS). Random immobilization of RML was carried out on these supports viadifferent amino acid residue of enzyme in a mild condition. In order to perform oriented immobilization, the epoxyfunctionalized support was partially modified by introducing iminodiacetic acid groups fallowed by addition of Cu2+. Inthis type of immobilization the enzyme was quickly adsorbed on the support by the most accessible histidine group viametal chelate affinity interaction. Then irreversible covalent immobilization was carried out by the reaction between thenucleophilic residues of RML and the remaining epoxy groups of the support after 24h of incubation. The results showedhigher thermal stability for immobilized derivatives compared to the soluble RML. The ability of the immobilizedpreparations to selective hydrolysis of fish oil was studied at different conditions. The results demonstrated that all thederivatives distinguish between cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA). According to effects of reaction parameters such as temperature, pH, time of hydrolysisprocess and amount of biocatalyst, increased discrimination of EPA and DHA.

کلیدواژه ها:

Rhizomucor miehei lipase ، Oriented immobilization ، Silica nanoparticles ، SBA-15 ، MCM-41 ، Fish oil