Free and Immobilised β-Glucosidases in Oenology: Biotechnological Characterisation and Its Effect on Enhancement of Wine Aroma

In grapes, monoterpenes and norisoprenoids are in the form of non-volatile compounds, flavourless glycosides which could enhance the aroma of wines after its hydrolysis using β- glucosidases enzymes. It is known that the use of immobilised enzymes offers advantages such as reusability and easy recuperation. In this study, a commercial β-glucosidase was immobilised by absorption in sodium alginate. Biotechnological characteristics and terpen hydrolysis (hydrolysis aroma precursors) in muscat wines were studied after treatment with both free and immobilised commercial β- glucosidase with two different concentrations. It was revealed that both forms shared an optimal pH (4.5) and a maximum temperature (64°C), even an increment on the activity between 40and 60°C. A similar Km value has been determined while Vmax from the immobilised enzyme was higher than the free (3.35 and 2.52 μmol min–1 mg–1, respectively). Additionally, the immobilised enzyme showed a better hydrolytic activity during 24 h, and its reusability has been proven. Regarding enzymatic hydrolysis in grape must, the best results were observed for the highest concentration of free β-glucosidase although glucose release was also determined for the immobilised enzyme along the days. In contrast, maximum activity was reached by the immobilised β-glucosidase in less time but in no case equalled the free ones. Finally, volatile compound liberation in wines treated with free or immobilised enzymes was analysed using HRGC-MS. Liberation for both enzymes and the greatest concentrations of some volatiles were detected when a double dose of the free β-glucosidase was used. Nevertheless, the wines treated with the immobilised β-glucosidase showed a high concentration of some volatile compounds such as nerol or geraniol.

One-pot biotransformation of glycerol into serinol catalysed by biocatalytic composites made of whole cells and immobilised enzymes

An immobilized biocatalytic cascade to transform glycerol into serinol provides a green and economically sustainable process.

A two-enzyme cascade reaction consisting of two reaction pathways. Studies in bulk solution for understanding the performance of a flow-through device with immobilised enzymes

A cascade reaction catalysed by bovine carbonic anhydrase (BCA) and horseradish peroxidase (HRP) proceeds over two possible pathways, which explains differences in product formation for differently immobilised enzymes in flow-through reactions.

Cell-free biocatalytic syntheses of l-pipecolic acid: a dual strategy approach and process intensification in flow

As an alternative to the traditional chemical synthesis or in vivo production of l-pipecolic acid, we have developed two ex vivo strategies using purified and immobilised enzymes for the production of this key building block.

H2-Driven biocatalytic hydrogenation in continuous flow using enzyme-modified carbon nanotube columns

We describe the implementation of a system of immobilised enzymes for H2-driven NADH recycling coupled to a selective biotransformation to enable H2-driven biocatalysis in flow.