“…CO 2 limitation is usually associated with a reduced productivity, with the development of the carbon concentrating mechanism (Moroney et al, 2011) and with a reduced PSII antenna size (Berger et al, 2014). In labscale experiments, electron transfer to O 2 (most probably Mehler-type) has also been found to be very effective in condition of reduced CO 2 availability in Chlamydomonas reinhardtii (Sueltemeyer et al, 1986;Bassi et al, 2012) and in Scenedesmus (Radmer and Kok, 1976;Radmer and Ollinger, 1980;Flameling and Kromkamp, 1998). Among the studies on microalgae mass culture, as far as we know, none directly compared high CO 2 (CO 2 supplemented) and low CO 2 (non CO 2 supplemented) conditions.…”