Encapsulation of chloroperoxidase in novel hybrid polysaccharide-silica biocomposites: Catalytic efficiency, re-use and thermal stability

• Chitosan-silica composites were used as immobilization support for CPO.
• A catalyst more efficient than in silica matrices alone was obtained.
• The optimized procedure shortened the whole process and increased enzyme efficiency.
• Immobilized CPO displayed an excellent thermal stability.
• CPO was reusable: the biocatalyst catalysed chloroxidation for up to 18 cycles.

Chloroperoxidase was encapsulated into hybrid polysaccharide-silica matrices by means of sol-gel processing. Chitosan was found to be the most effective additive to improve enzyme catalytic performances. At the standard initial experimental conditions, enzyme was able to perform five complete reaction cycles and a substrate conversion of 60% at the sixth cycle. The optimization of the procedure, which consisted in the reduction of reaction time, the elimination of washes between cycles and the increase of the chitosan concentration in matrices, allowed a considerably higher reusability of the biocatalyst, up to 18 consecutive reaction cycles.Moreover, immobilized enzyme displayed an excellent thermal stability and even at 70 °C its activity remained higher than 95% also after 2 h of incubation.These results paved the way to the application of chloroperoxidase for academic synthesis and industrial production of chemicals.

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