Screening New Xylanase Biocatalysts from the Mangrove Soil Diversity

Corinne Ivaldi (1) , Mariane Daou (2, 3) , Laurent Vallon (4) , Alexandra Bisotto (2) , Mireille Haon (2) , Sona Garajova (2) , Emmanuel Bertrand (2) , Craig B Faulds (2) , Giuliano Sciara (2) , Adrien Jacotot (5, 6, 7, 8) , Cyril Marchand (7, 8) , Mylène Hugoni (2) , Harivony Rakotoarivonina (1) , Marie-Noëlle Rosso (2) , Caroline Rémond (1) , Patricia Luis (4) , Eric Record (2)

1 FARE - Fractionnement des AgroRessources et Environnement
2 BBF - Biodiversité et Biotechnologie Fongiques
3 Khalifa University
4 LEM - Laboratoire d'Ecologie Microbienne - UMR 5557
5 ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327
6 Biogéosystèmes Continentaux - UMR7327
7 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
8 ISEA - Institut de sciences exactes et appliquées

Mangrove sediments from New Caledonia were screened for xylanase sequences. One enzyme was selected and characterized both biochemically and for its industrial potential. Using a specific cDNA amplification method coupled with a MiSeq sequencing approach, the diversity of expressed genes encoding GH11 xylanases was investigated beneath Avicenia marina and Rhizophora stylosa trees during the wet and dry seasons and at two different sediment depths. GH11 xylanase diversity varied more according to tree species and season, than with respect to depth. One complete cDNA was selected (OFU29) and expressed in Pichia pastoris. The corresponding enzyme (called Xyn11-29) was biochemically characterized, revealing an optimal activity at 40–50 °C and at a pH of 5.5. Xyn11-29 was stable for 48 h at 35 °C, with a half-life of 1 h at 40 °C and in the pH range of 5.5–6. Xyn11-29 exhibited a high hydrolysis capacity on destarched wheat bran, with 40% and 16% of xylose and arabinose released after 24 h hydrolysis. Its activity on wheat straw was lower, with a release of 2.8% and 6.9% of xylose and arabinose, respectively. As the protein was isolated from mangrove sediments, the effect of sea salt on its activity was studied and discussed.

Mots clés: lignocellulose degrading enzymes; xylanases; heterologous expression; biomass degradation; marine fungus; mangrove; salt adaptation

Domaines: Planète et Univers [physics]; Interfaces continentales, environnement

Corinne Ivaldi, Mariane Daou, Laurent Vallon, Alexandra Bisotto, Mireille Haon, et al.. Screening New Xylanase Biocatalysts from the Mangrove Soil Diversity. Microorganisms, 2021, 9 (7), pp.1-16. ⟨10.3390/microorganisms9071484⟩. ⟨insu-03293424⟩