Characterization and Dye Decolorization Potential of Two Laccases from the Marine-Derived Fungus Pestalotiopsis sp.

Saowanee Wikee (1) , Juliette Hatton (2) , Annick Turbé-Doan (3) , Yann Mathieu (3) , Marianne Daou (3) , Anne Lomascolo (3) , Abhishek Kumar (4) , Saisamorn Lumyong (1) , Giuliano Sciara (3) , Craig B. Faulds (3) , Eric Record (3)

1 CMU - Chiang Mai University
2 Sup'Biotech
3 BBF - Biodiversité et Biotechnologie Fongiques
4 CAU - Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel

Two laccase-encoding genes from the marine-derived fungus Pestalotiopsis sp. have been cloned in Aspergillus niger for heterologous production, and the recombinant enzymes have been characterized to study their physicochemical properties, their ability to decolorize textile dyes for potential biotechnological applications, and their activity in the presence of sea salt. The optimal pH and temperature of PsLac1 and PsLac2 differed in relation to the substrates tested, and both enzymes were shown to be extremely stable at temperatures up to 50 • C, retaining 100% activity after 3 h at 50 • C. Both enzymes were stable between pH 4-6. Different substrate specificities were exhibited, and the lowest K m and highest catalytic efficiency values were obtained against syringaldazine and 2,6-dimethoxyphenol (DMP) for PsLac1 and PsLac2, respectively. The industrially important dyes-Acid Yellow, Bromo Cresol Purple, Nitrosulfonazo III, and Reactive Black 5-were more efficiently decolorized by PsLac1 in the presence of the redox mediator 1-hydroxybenzotriazole (HBT). Activities were compared in saline conditions, and PsLac2 seemed more adapted to the presence of sea salt than PsLac1. The overall surface charges of the predicted PsLac three-dimensional models showed large negatively charged surfaces for PsLac2, as found in proteins for marine organisms, and more balanced solvent exposed charges for PsLac1, as seen in proteins from terrestrial organisms.

Mots clés: Pestalotiopsis; laccase; salt tolerance; dye decolorization; heterologous expression

Domaines: Ingénierie de l'environnement; Biotechnologies

Saowanee Wikee, Juliette Hatton, Annick Turbé-Doan, Yann Mathieu, Marianne Daou, et al.. Characterization and Dye Decolorization Potential of Two Laccases from the Marine-Derived Fungus Pestalotiopsis sp.. International Journal of Molecular Sciences, 2019, 20 (8), pp.1864. ⟨10.3390/ijms20081864⟩. ⟨hal-02276821⟩