Impact of seconds to minutes photoperiods on Chlorella vulgaris growth rate and chlorophyll a and b content

Wendie Levasseur (1, 2) , Behnam Taidi (1, 2) , Robin Lacombe (1) , Patrick Perre (1, 2) , Victor Pozzobon (1, 2)

1 LGPM - Laboratoire de Génie des Procédés et Matériaux - EA 4038
2 CEBB - Centre Européen de Biotechnologies et Bioéconomie

In order to determine the impact of photoperiod duration, Chlorella vulgaris was studied in low cell density batch culture for seven days. Different photoperiod cycles ranging from minutes to seconds intervals were applied and their impact on microalgae cells growth and chlorophyll a and b contents were compared against a reference culture that was continuously illuminated. The selected photoperiods are typical of those due to alternance of dark and light zones along the algae trajectories inside photobioreactors. Throughout this study, all cultures received the same total amount of photons. When photoperiods of minutes duration were applied, the cells grew more slowly (0.052 ± 0.003 h−1) but contained higher average contents of chlorophyll pigments (0.27 ± 0.03 pg⋅cell−1) than those cells grown under continuous illumination (0.062 ± 0.003 h−1 and 0.42 ± 0.08 pg⋅cell−1, respectively). Cultures exposed to photoperiods of seconds duration grew the fastest (0.072 ± 0.002 h−1) with fewer photosynthetic units (0.61 ± 0.08 pg⋅cell−1) than the cells grown with continuous illumination. These results suggest that light harvesting systems have a higher efficiency with photoperiods of duration in the seconds range.

Mots clés: Microalgae; Light; Photoperiod; Growth rate; Chlorophyll; Photosynthesis efficiency

Domaines: Biotechnologies

Wendie Levasseur, Behnam Taidi, Robin Lacombe, Patrick Perre, Victor Pozzobon. Impact of seconds to minutes photoperiods on Chlorella vulgaris growth rate and chlorophyll a and b content. Algal Research - Biomass, Biofuels and Bioproducts, 2018, 36, pp.10-16. ⟨10.1016/j.algal.2018.10.007⟩. ⟨hal-01959262⟩