energy conversion point of view, through the solar spectrum. According to Bergene
(1996), this ratio provides the value of process efficiency. In this work, the theoretical upper efficiency of water photolysis by microalgae was 0.11. Comparatively,
commercial photovoltaic solar cells convert solar energy with efficiency in the
range of 0.10–0.15.
Another important measure is the photosynthetic quotient (PQ), which provides
more accurate values of the components involved in photosynthesis. The PQ is the
molar ratio between released oxygen (gross primary production) in water photolysis
during light reactions and CO 2 converted during the Calvin–Benson–Bassham
cycle, and it varies as a function of the nitrogen source, carbon/nitrogen ratio
assimilated, microalgae species used, type of organic molecule produced, luminous
intensity, and photoperiods (Eriksen et al. 2007; Smith et al. 2012).
To accurately measure the photosynthetic activity, the PQ can be calculated
according to Eq. 2 (Kliphuis et al. 2010):
PQ ¼
OPR
CUR
ð2Þ
where OPR is the oxygen production rate, and CUR is the carbon dioxide consumption rate.
Generally, the experimental values of the PQ are close to 1.0 (Burris 1981).
Table 4 shows the experimental values of the PQ found in different microalgae.
Jacob-Lopes et al. (2010) found a PQ of 0.74, which result corroborates the theoretical value estimated through the photosynthetic equation, establishing that each
1 kg of CO 2 consumed corresponds to a release of 0.73 kg O 2 .
Fig. 2 Schematic representation of the oxygen generation in the photosynthesis
280
I. Aguiar Severo et al.
(1996), this ratio provides the value of process efficiency. In this work, the theoretical upper efficiency of water photolysis by microalgae was 0.11. Comparatively,
commercial photovoltaic solar cells convert solar energy with efficiency in the
range of 0.10–0.15.
Another important measure is the photosynthetic quotient (PQ), which provides
more accurate values of the components involved in photosynthesis. The PQ is the
molar ratio between released oxygen (gross primary production) in water photolysis
during light reactions and CO 2 converted during the Calvin–Benson–Bassham
cycle, and it varies as a function of the nitrogen source, carbon/nitrogen ratio
assimilated, microalgae species used, type of organic molecule produced, luminous
intensity, and photoperiods (Eriksen et al. 2007; Smith et al. 2012).
To accurately measure the photosynthetic activity, the PQ can be calculated
according to Eq. 2 (Kliphuis et al. 2010):
PQ ¼
OPR
CUR
ð2Þ
where OPR is the oxygen production rate, and CUR is the carbon dioxide consumption rate.
Generally, the experimental values of the PQ are close to 1.0 (Burris 1981).
Table 4 shows the experimental values of the PQ found in different microalgae.
Jacob-Lopes et al. (2010) found a PQ of 0.74, which result corroborates the theoretical value estimated through the photosynthetic equation, establishing that each
1 kg of CO 2 consumed corresponds to a release of 0.73 kg O 2 .
Fig. 2 Schematic representation of the oxygen generation in the photosynthesis
280
I. Aguiar Severo et al.