Photosynthetic performance of Chlorella vulgaris R117 mass culture is moderated by diurnal oxygen gradients in an outdoor thin layer cascade

Tomás Agustín Rearte, Paula S.M. Celis-Plá, Amir Neori, Jiří Masojídek, Giuseppe Torzillo, Cintia Gómez-Serrano, Ana Margarita Silva Benavides, Félix Álvarez-Gómez, R. T. Abdala-Díaz, Karolína Ranglová, Martín Caporgno, Thaís Fávero Massocato, Jaqueline Carmo da Silva, Hafidh Al Mahrouqui, Richard Atzmüller, Félix L. Figueroa

Research output: Contribution to journalArticlepeer-review


Dissolved oxygen concentration is a critical point for microalgae in large scale cultivation systems. Highly productive cultures inevitably generate a build-up of oxygen gradients along the reactor which can affect photosynthetic performance. In this study, a fast-growing strain of Chlorella vulgaris R117 was cultured outdoors in a thin-layer cascade during a one-week trial reaching a biomass productivity of 4 g DW L−1 d−1 (27 g DW m−2 d−1). High photosynthetic activity led to oxygen oversaturation of up to 400% in some parts along the culture units at midday. The aim was to examine the effect of high dissolved oxygen concentration on diurnal changes in the photosynthetic performance and growth of the Chlorella culture using multi-technique approach. Photosynthetic activity of Chlorella R117 culture was estimated in situ and ex situ using oxygen production and in vivo Chl a fluorescence measurements, which showed good correlation. The rates of electron transport and of oxygen production were related, but the values of the μmolelectrons/μmolO2 ratio was higher than predicted, suggesting the probable involvement of electron and oxygen consuming processes such as photorespiration and Mehler reaction. These processes probably function as photoprotective mechanisms, since no photodamage was observed in the Chlorella R-117 cultures. Depression (down-regulation) of photosynthetic activity due to the exposition to high dissolved oxygen concentration along the cascade area over time was observed. The usefulness of on-line measurements was demonstrated to obtain immediate and in-situ information on the physiological status of the culture. This data can be used in models of operation control for large-scale microalgae production units.

Original languageEnglish
Article number102176
JournalAlgal Research
StatePublished - Apr 2021

Bibliographical note

Publisher Copyright:
© 2020 Elsevier B.V.


  • Chlorophyll fluorescence monitoring
  • Outdoor mass cultivation
  • Oxygen production
  • PSII down-regulation
  • Photoadaptation

ASJC Scopus subject areas

  • Agronomy and Crop Science


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