Enzyme Properties of a Laccase Obtained from the Transcriptome of the Marine-Derived Fungus Stemphylium lucomagnoense

Wissal Ben Ali (1) , Amal Ben Ayed (1) , Annick Turbé-Doan (1) , Emmanuel Bertrand (1) , Yann Mathieu (2) , Craig B Faulds (1) , Anne Lomascolo (1) , Giuliano Sciara (1) , Eric Record (1) , Tahar Mechichi (3)

1 BBF - Biodiversité et Biotechnologie Fongiques
2 UBC - University of British Columbia
3 ENIS - École Nationale d'Ingénieurs de Sfax | National School of Engineers of Sfax

Only a few studies have examined how marine-derived fungi and their enzymes adapt to salinity and plant biomass degradation. This work concerns the production and characterisation of an oxidative enzyme identified from the transcriptome of marine-derived fungus Stemphylium lucomagnoense. The laccase-encoding gene SlLac2 from S. lucomagnoense was cloned for heterologous expression in Aspergillus niger D15#26 for protein production in the extracellular medium of around 30 mg L −1. The extracellular recombinant enzyme SlLac2 was successfully produced and purified in three steps protocol: ultrafiltration, anion-exchange chromatography, and size exclusion chromatography, with a final recovery yield of 24%. SlLac2 was characterised by physicochemical properties, kinetic parameters, and ability to oxidise diverse phenolic substrates. We also studied its activity in the presence and absence of sea salt. The molecular mass of SlLac2 was about 75 kDa, consistent with that of most ascomycete fungal laccases. With syringaldazine as substrate, SlLac2 showed an optimal activity at pH 6 and retained nearly 100% of its activity when incubated at 50 • C for 180 min. SlLac2 exhibited more than 50% of its activity with 5% wt/vol of sea salt.

Mots clés: laccase; Stemphylium; heterologous expression; enzyme properties; alkaline; salt tolerance

Domaines: Génie des procédés; Alimentation et Nutrition; Biotechnologies; Ingénierie des aliments; Biochimie [q-bio.BM]

Wissal Ben Ali, Amal Ben Ayed, Annick Turbé-Doan, Emmanuel Bertrand, Yann Mathieu, et al.. Enzyme Properties of a Laccase Obtained from the Transcriptome of the Marine-Derived Fungus Stemphylium lucomagnoense. International Journal of Molecular Sciences, 2020, 21 (21), pp.8402. ⟨10.3390/ijms21218402⟩. ⟨hal-03000290⟩