Immobilization study of a monomeric oleate hydratase from Rhodococcus erythropolis

The chemical, pharmaceutical, and cosmetic industries are currently confronted with the challenge of transitioning from traditional chemical processes to more sustainable biocatalytic methods. To support that aim, we developed various heterogeneous biocatalysts for an industrially relevant enzyme called oleate hydratase that converts oleic acid to 10-hydroxystearic acid, a fatty emollient substance useful for various technical applications. We used cheap support matrices such as silica, chitosan, cellulose, and agarose for further scale-up and economic feasibility at the industrial level alongside more sophisticated supports like metal–organic frameworks. Different physical and chemical binding approaches were employed. Particularly, by immobilizing oleate hydrates on a 3-aminopropyltriethoxysilane surface-functionalized cellulose matrix, we developed an enzyme immobilizate with almost 80% activity of the free enzyme. The long-term goal of this work was to be able to use the developed heterogeneous biocatalyst for multiple reuse cycles enabling profitable biocatalysis. Despite high initial conversion rate by the developed cellulose-based immobilizate, a depletion in enzyme activity of immobilized oleate hydratase was observed over time. Therefore, further enzyme modification is required to impart stability, the optimization of operational conditions, and the development of carrier materials that enable economical and sustainable enzymatic conversion of oleic acid to meet the commercial demand.

Graphical abstract