ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Differential scanning calorimetry (DSC) as a tool for studying thermal properties of a crude cellulase cocktail

Paola Di Matteo, Francesca Luziatelli, Martina Bortolami, Maria Luisa Mele, Maurizio Ruzzi, and Paola Russo

Department of Basic and Applied Sciences for Engineering (SBAI), Sapienza University of Rome, Rome, Italy

E-mail: p.dimatteo@uniroma1.it

Received: 2 November 2022  Accepted: 29 December 2022

Abstract:

Abstract

Differential scanning calorimetry (DSC) was used as an efficient and rapid tool in studying the conformational transitions between the folded and unfolded structures of cellulolytic enzymes. The thermal properties of two crude hydrolytic enzyme cocktails containing extracellular cellulases from Trichoderma longibrachiatum DIBAF-10 were analyzed and compared with three commercial cellulase preparations. Differences in the thermal behavior of fungal cellulases in the liquid phase, freeze-dried state, liquid formulations in sodium citrate buffer (pH 4.8), and contact with cellulose, carboxymethyl cellulose, and cellobiose were evaluated. DSC profiles of cellulases from the DIBAF-10 strain provided important thermodynamic information about the thermal stability of the included proteins. Crude enzyme cocktails underwent a reproducible and irreversible exothermic aggregation phenomenon at 52.45 ± 0.90 °C like commercial β-glucosidase. Freeze-dried and resuspended in a sodium citrate buffer, cellulases from T. longibrachiatum showed an endothermic peak dependent on buffer and enzyme concentration. In the enzyme-substrates systems, a shift of the same peak was recorded for all substrates tested. The thermal analysis of freeze-dried cellulase samples in the range of 20–150 °C gave information on the denaturation process. In conclusion, we demonstrated that DSC is a cost-effective tool for obtaining "conformational fingerprinting" of crude fungal cellulase preparations.

Graphical abstract

Keywords: Differential scanning calorimetry; Cellulase activity; Cellulase stability; Trichoderma longibrachiatum; Thermal stability

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02658-3

Chemical Papers 77 (5) 2689–2696 (2023)