|Title||Astin C Production by the Endophytic Fungus Cyanodermella asteris in Planktonic and Immobilized Culture Conditions|
|Author(s)||Vassaux, Antoine; Tarayre, Cédric; Arguëlles-Arias, Anthony; Compère, Philippe; Delvigne, Frank; Fickers, Patrick; Jahn, Linda; Lang, Alexander; Leclère, Valérie; Ludwig-Müller, Jutta; Ongena, Marc; Schafhauser, Thomas; Telek, Samuel; Théatre, Ariane; Berkel, Willem J.H. van; Vandenbol, Micheline; Pée, Karl Heinz van; Willems, Luc; Wohlleben, Wolfgang; Jacques, Philippe|
|Source||Biotechnology Journal 14 (2019)8. - ISSN 1860-6768|
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||astin C - biofilms - Cyanodermella asteris - immobilized-cell cultures - secondary metabolites|
The fungal endophyte Cyanodermella asteris (C. asteris) has been recently isolated from the medicinal plant Aster tataricus (A. tataricus). This fungus produces astin C, a cyclic pentapeptide with anticancer and anti-inflammatory properties. The production of this secondary metabolite is compared in immobilized and planktonic conditions. For immobilized cultures, a stainless steel packing immersed in the culture broth is used as a support. In these conditions, the fungus exclusively grows on the packing, which provides a considerable advantage for astin C recovery and purification. C. asteris metabolism is different according to the culture conditions in terms of substrate consumption rate, cell growth, and astin C production. Immobilized-cell cultures yield a 30% increase of astin C production, associated with a 39% increase in biomass. The inoculum type as spores rather than hyphae, and a pre-inoculation washing procedure with sodium hydroxide, turns out to be beneficial both for astin C production and fungus development onto the support. Finally, the influence of culture parameters such as pH and medium composition on astin C production is evaluated. With optimized culture conditions, astin C yield is further improved reaching a five times higher final specific yield compared to the value reported with astin C extraction from A. tataricus (0.89 mg g−1 and 0.16 mg g−1 respectively).