202
J.-F. Cornet et al.
Table 6. Modifications in the ratio proteins/exopolysaccharide (EPS) for different conditions of
incident radiant light fluxes on the photobioreactor cultivating S. platensis
Incident light
Batch cultures [87]
flux
(W.m 2)
Proteins (%w)
EPS (%w)
Continuous cultures [86]
Proteins (%w)
EPS (%w)
10 • 1
65
10
50 • 5
59
16
-
-
120 • 10
57
19
56
20
160 • 15
-
-
48
27
200 • 20
43
33
42
34
300 • 30
41
35
-
-
4.3.2 Definition of Overall Absorption and Scattering Mass Coefficients
The definition of absorption and scattering coefficients introduced in Sect. 3
have to be modified to take into account the modifications of pigment concentrations and cell size that occur in batch cultures during mineral limitations.
Scattering is related to the size of cells suspended in the medium and is thus
proportional to the mass concentration of the total biomass concentration CXT,
whereas absorption depends on pigment concentrations; absorption is thus
proportional to the phycocyanin and chlorophyll content of cells, i.e. to the sum
Cec +Ccn, called the antenna content. For a rectangular reactor illuminated on
one side and assuming the one-dimensional approximation of Schuster, the
parameters at and 6 of the light transfer model (Table 3) can thus be expressed as
= [Ea(Cec + Ccn)/[Ea(Cac +Ccn) + ESCxT]] 1/2
(102)
= [Ea(Cpc + CcH)[Ea(Cpc + CCH ) -~- ESCxT]]I/2L
(103)
The light transfer equations derived from Schuster's assumptions clearly depend
on both the biomass concentration and the pigment content of the cells. It is
therefore justified a posterior• to describe absorption and scattering phenomena,
which play different roles in light diffusion inside the reacting volume, by two
coefficients. These overall absorption and scattering mass coefficients may be
rewritten with these definitions:
Ea = 950 m2.kg- 1 of antenna
Es = 182m2.kg - 1 of total biomass
4.3.3 Kinetic Model [73]
Two additional assumptions are needed to establish the different kinetic equations for each component of the model.
J.-F. Cornet et al.
Table 6. Modifications in the ratio proteins/exopolysaccharide (EPS) for different conditions of
incident radiant light fluxes on the photobioreactor cultivating S. platensis
Incident light
Batch cultures [87]
flux
(W.m 2)
Proteins (%w)
EPS (%w)
Continuous cultures [86]
Proteins (%w)
EPS (%w)
10 • 1
65
10
50 • 5
59
16
-
-
120 • 10
57
19
56
20
160 • 15
-
-
48
27
200 • 20
43
33
42
34
300 • 30
41
35
-
-
4.3.2 Definition of Overall Absorption and Scattering Mass Coefficients
The definition of absorption and scattering coefficients introduced in Sect. 3
have to be modified to take into account the modifications of pigment concentrations and cell size that occur in batch cultures during mineral limitations.
Scattering is related to the size of cells suspended in the medium and is thus
proportional to the mass concentration of the total biomass concentration CXT,
whereas absorption depends on pigment concentrations; absorption is thus
proportional to the phycocyanin and chlorophyll content of cells, i.e. to the sum
Cec +Ccn, called the antenna content. For a rectangular reactor illuminated on
one side and assuming the one-dimensional approximation of Schuster, the
parameters at and 6 of the light transfer model (Table 3) can thus be expressed as
= [Ea(Cec + Ccn)/[Ea(Cac +Ccn) + ESCxT]] 1/2
(102)
= [Ea(Cpc + CcH)[Ea(Cpc + CCH ) -~- ESCxT]]I/2L
(103)
The light transfer equations derived from Schuster's assumptions clearly depend
on both the biomass concentration and the pigment content of the cells. It is
therefore justified a posterior• to describe absorption and scattering phenomena,
which play different roles in light diffusion inside the reacting volume, by two
coefficients. These overall absorption and scattering mass coefficients may be
rewritten with these definitions:
Ea = 950 m2.kg- 1 of antenna
Es = 182m2.kg - 1 of total biomass
4.3.3 Kinetic Model [73]
Two additional assumptions are needed to establish the different kinetic equations for each component of the model.