Search

In this work, the adsorption of Candida antarctica B (CALB) and Rhizomucor miehei (RML) lipases into hydrophobic wrinkled silica nanoparticles (WSNs) is investigated. WSNs are hydrophobized by chemical vapor deposition. Both proteins are homogeneously distributed inside the pores of the nanoparticles, as confirmed by Transmission Electron Microscopy and Energy Dispersive X-ray measurements. The maximum enzyme load of CALB is twice that obtained for RML. Fourier Transform Infrared Spectroscopy confirms the preservation of the enzyme secondary structure after immobilization for both enzymes. Adsorption isotherms fit to a Langmuir model, resulting in a binding constant (K L ) for RML 4.5-fold higher than that for CALB, indicating stronger binding for the former. Kinetic analysis reveals a positive correlation between enzyme load and RML activity unlike CALB where activity decreases along the enzyme load increases. Immobilization allows for enhancing the thermal stability of both lipases. Finally, CALB outperforms RML in the hydrolysis of ethyl-3-hydroxybutyrate. However, immobilized CALB yielded 20 % less 3-HBA than free lipase, while immobilized RML increases 3-fold the 3-HBA yield when compared with the free enzyme. The improved performance of immobilized RML can be explained due to the interfacial hyperactivation undergone by this lipase when immobilized on the superhydrophobic surface of WSNs., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

β-glucosidase (BG) plays a key role in determining the efficiency of the enzymatic complex cellulase for the degradation of cellulose into sugars. It hydrolyses the cellobiose, an inhibitor of the enzymatic complex. Therefore, the immobilization of BG is a great challenge for the industrial application of cellulases. Cellulases usually contains a BG amount insufficient to avoid inhibition by cellobiose. Here the BG was immobilized by matrix assisted pulsed laser evaporation (MAPLE) technique. The frozen matrix was composed of water, water/m-DOPA and water/m-DOPA/quinone. The effect of the excipients on the final conformation of the enzyme after the MAPLE processing was determined. The enzyme secondary structure was studied by FTIR analysis. The catalytic performances of the deposited films were tested in the cellobiose hydrolysis reaction. The results demonstrate that the presence of the oxidized form of m-DOPA, the O-quinone form, can protect the protein native structure, with the laser inducing little or no damage. In fact, only the samples deposited from this target preserved the secondary structure of the polypeptide chain and allowed a complete hydrolysis of cellobiose for four consecutive runs, showing a high operational stability of the biocatalyst., (Copyright © 2019 Elsevier Inc. All rights reserved.)