Effects of hormones on the growth and metabolite production of Amphidinium carterae under carbon sufficient and carbon limited conditions

• Published in: Algal research (Amsterdam) 2025-01, Vol.85, p.103810, Article 103810
• Main Authors: Kichouh-Aiadi, S., López-Rosales, L., Gallardo-Rodríguez, J.J., Cerón-García, M.C., Sánchez-Mirón, A., García-Camacho, F.
• Format: Article
• Language: English
• Subjects: Amphidinium; Amphidinols; Dinofagellate; Hormones; Inorganic carbon limitation; Microalga
• ISSN: 2211-9264; 2211-9264
• DOI: 10.1016/j.algal.2024.103810

The dinoflagellate Amphidinium carterae produces valuable fatty acids, pigments, and bioactive polyketides (e.g., amphidinols). Despite recent advances in its intensive cultivation, challenges remain that justify further work. This study explored the effects of phytohormone supplementation on growth and metabolism using a One Strain Many Compounds (OSMAC) approach. Auxins, cytokinins, jasmonates, amines, abscisic acid, gibberellic acid, and other signaling molecules were screened in batch cultures. Synthetic auxin 2-naphthoxyacetic acid (BNOA) at a final concentration of 14.84 μM (3 mg·L−1) emerged as the most stimulant. On a small scale, BNOA increased biomass productivity by up to 32 % and hemolytic activity in terms of productivity by 50 %. Scaling up in 10 L bubble column photobioreactor cultures with the addition of BNOA, but without CO2 supplementation, resulted in levels of amphidinol production comparable to those achieved with CO2 addition. Compared to the control without BNOA, BNOA cultures generated 2.2-fold more biomass during the stationary growth phase, and amphidinol production increased fourfold per unit of biomass. This work reveals that the addition of exogenous phytohormones such as BNOA can sustain the production of valuable metabolites in A. carterae, eliminating the need for additional CO2 and its associated costs. This promising approach highlights the potential of hormone supplementation as a cost-effective and efficient cultivation strategy for dinoflagellate bioprocesses. •12 hormones from 8 different groups were evaluated.•2-Naphthoxyacetic acid (BNOA) the most potent growth enhancer.•Scaled up cultures with BNOA without CO2 addition maintained amphidinol production levels.•Scaled up cultures with BNOA without CO2 addition generated 2.2-fold more biomass.•First time addition of exogenous phytohormones sustains the production of the valuable metabolites in A. carterae cultures.