Effects of blue light on the biochemical composition and photosynthetic activity of Isochrysis sp. (T-iso)

In aquaculture, particularly in bivalve hatcheries, the biochemical composition of algal diets has a strong influence on larval and post-larval development. Biochemical composition is known to be related to culture conditions, among which light represents a major source of variation. The effects of blue light on biochemical composition and photosynthetic rate of Isochrysis sp. (T-iso) CCAP 927/14 were assessed in chemostat at a single irradiance (300 μmol photons m−2 s−1) and compared with white light. Two different dilution (renewal) rates were also tested: 0.7 and 0.2 d−1. Relative carbohydrate content was lower under blue light than under white light at both dilution rates, whereas chlorophyll a and photosynthesis activity were higher. In contrast, carbon quota was lower and protein content higher under blue light than under white light, but only at 0.7 d−1. Despite these metabolic differences, cell productivity was not significantly affected by the spectrum. However, the nitrogen to carbon ratio and photosynthetic activity were higher at 0.7 d−1 than at 0.2 d−1, while carbon quota and carbohydrate content were lower. Our results show that blue light may influence microalgal metabolism without reducing productivity for a given growth rate, a result that should be of great interest for microalgal production in aquaculture.


Isochrysis, Blue light, Photosynthesis, Proximate composition, Chemostat

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Marchetti Julie, Bougaran Gael, Jauffrais Thierry, Lefebvre Sebastien, Rouxel Catherine, Saint-Jean Bruno, Lukomska Ewa, Robert Rene, Cadoret Jean-Paul (2013). Effects of blue light on the biochemical composition and photosynthetic activity of Isochrysis sp. (T-iso). Journal Of Applied Phycology. 25 (1). 109-119. https://doi.org/10.1007/s10811-012-9844-y, https://archimer.ifremer.fr/doc/00085/19599/

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