A method to assess algicidal activity of microalgal extracts coupling microalgae produced in stirred closed photobioreactor operating in continuous with pulse amplitude modulated (PAM) fluorometry

Eva Menguy; Vincent Dumontet; Noémie Coulombier; Vincent Meriot; Loïc Le Déan; Vanille Barthelemy; Thierry Jauffrais

doi:10.1016/j.mex.2020.101037

A method to assess algicidal activity of microalgal extracts coupling microalgae produced in stirred closed photobioreactor operating in continuous with pulse amplitude modulated (PAM) fluorometry

MethodsX. 2020 Aug 19:7:101037. doi: 10.1016/j.mex.2020.101037. eCollection 2020.

Authors

Eva Menguy¹, Vincent Dumontet², Noémie Coulombier³, Vincent Meriot³, Loïc Le Déan¹, Vanille Barthelemy¹, Thierry Jauffrais¹

Affiliations

¹ Ifremer, IRD, Univ Nouvelle-Calédonie, Univ La Réunion, CNRS, UMR 9220 ENTROPIE, 101 Promenade Roger Laroque, 98897 Noumea, New Caledonia.
² Université Paris Saclay, CNRS, UPR 2301, ICSN, 1 Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France.
³ ADECAL Technopole, 1 bis rue Berthelot, 98846 Noumea, New Caledonia.

Abstract

We describe in the present study a quick and reliable method based on chlorophyll a fluorescence to assess putative algicidal effect of different microalgal extracts. We couple microalgal production under chemostat cultivation mode to continuously produce a given microalgae species (e.g. Dunaliella salina in this study) at a stable physiological state to ease comparison between extracts tested; with a non-destructive method based on chlorophyll a fluorescence. Pulse amplitude modulated (PAM) fluorometry was used to assess over time the effect of different microalgal crude extracts on the efficiency of the photosystem II (PSII) of a tested microalgae (Dunaliella salina). • Microalgal production at stationary phase in stirred closed photobioreactor (PBR) operating in continuous have stable photophysiological parameters, which is a prerequisite to compare the impact of different algicidal compounds. • The combination of both methods, allows to quickly assess the algicidal effect of diverse microalgal (crude) extracts on the PSII efficiency of a tested microalgae. • The method may be used to identify and isolate algicidal molecules affecting algal PSII using a bio-guided isolation protocol.

Keywords: Anti algal; Bioassay; Cytoxicity; Fv/Fm; Microalgae; NPQ; Non photochemical quenching; Phytochemistry; Quantum efficiency; electron transport rate.