Greener and cheaper alternatives to petrol-based supports have been studied in recent years to implement biocatalysis in industrial processes exploiting enzyme immobilization. Among these, hydroxyapatite (HAP), represents a suitable candidate thanks to its structural stability, non-toxicity, large surface area, and ease of surface modification. As it can be sourced from waste, it fulfills also the circular economy principles. This work explored the use of HAP for covalent immobilization using three model enzymes: a vanadium-dependent chloroperoxidase from Curvularia inaequalis(CiVCPO), a l-tyrosine decarboxylase from Lactobacillus brevis (LbTDC) and an R-selective transaminase from Thermomyces stellatus (TsRTA). Different strategies were tested, and the derivatization with (3-aminopropyl)triethoxysilane (APTES) followed by glutaraldehyde activation was found to be the most widely applicable. LbTDC and TsRTA immobilized through this strategy were tested in multiple reaction cycles to assess their stability and reusability with promising results.

Great work in collaboration with the University of Milan. Well done to Leonardo Gelati for bringing this home!

Read the full paper here