Laccase from Pleurotus sajor-caju on functionalised SBA-15 mesoporous silica: Immobilisation and use for the oxidation of phenolic compounds

Abstract: Laccase from Pleurotus sajor-caju was immobilised on functionalised SBA-15 mesoporous silica. The immobilisation process reached the equilibrium after about 100min. In order to study the effect of loading (L) on activity of the immobilised laccase, the adsorption isotherm was built and the activity of the corresponding immobilised biocatalysts was determined. The activity of the immobilised preparations reached a maximum at L =217kUgSBA-15 −1, whereas higher loadings gave rise to a less-efficient biocatalyst. The immobilised laccase was used for the oxidation of a mixture of four phenolic compounds (protocatechuic acid, ferulic acid, sinapic acid and caffeic acid) chosen among those present in olive mill wastewaters (OMWs). These compounds determine the phytotoxicity of OMWs. Different reaction rates were observed for the oxidation of the examined phenolic compounds. The biocatalyst was recycled and a conversion of 84mol% at the 10th reuse and of about 60mol% after the 14th reuse was obtained. In conclusion, the laccase immobilised on SBA-15 is a potential biocatalyst for bioremediation of OMWs, which is an important environmental problem in the regions around the Mediterranean Sea. [Copyright &y& Elsevier]