Kinetics and Energetics of Photosynthetic Micro-Organisms in Photobioreactors
217
The resolution of the system of Eqs. (148), (149) and (150) gives the expression of x:
- 1 + x/1 -- q2
X -(152)
q
SO that x = - 0.644 for q = 0.910.
This value ofx corresponds to P/2e- = 1.71 (Eq. 145). Using Eqs. (134), (135)
and (141) with x = q = 0.91 leads to recalculation of the affinities and the value
of the effective radiant energy which is converted into chemical energy:
(hV)eff = 76.6 kJ.mol- 1
AAXp = 197.3 kJ.mol- 1
AcoF = -- 139.7 kJ.mol- 1
The difference between the incident radiant energy hv = 176.4 kJ.mol-1 and the
effective value (hv)eff represents the part of radiant energy dissipated into heat at
the antenna level. It can be interpreted as an adaptative control of the photosysterns when the light energy is provided in non-limiting conditions.
2) When the light energy transfer is the rate limiting process, the external
constraint now concerns the rate JATP. The f-function is then expressed as follows:
JATP = LAAAATP( 1 + qx) = K
(153)
The solution of Eqs. (148), (149) and (150) gives x = 0 which in turns leads to
P/2e- = 1.21, Aco F = 0 and (hv)eff = 216.4 kJ.mol-1. Obviously, the effective
radiant energy cannot be greater than the incident radiant energy value which
explains that for very limiting incident energy fluxes below the compensation
point, chemical energy is supplied by respiration.
6.1.3 Comparison of Experimental and Theoretical Values of P/2eThe experimental determination of the biomass composition enables one to
calculate the overall P/2e- ratio by the weighted sum of different P/2e- for the
synthesis of the fractions of cell material. Importantly, such calculations are only
feasible if a biochemically structured approach to metabolism is used. The
values of P/2e- obtained for the synthesis of the different parts of the biomass
are given in Table 2.
To test the applicability of the previous theoretical developments, the influence of three different cases of limitation on the biomass composition has been
investigated.
6.1.3.1 Light Energy Transfer Limitation
The cultures performed at a low light energy incident flux are considered
(Fo < 20W.m -2, non-limiting part of Figs. 10-12). As stated above, total
217
The resolution of the system of Eqs. (148), (149) and (150) gives the expression of x:
- 1 + x/1 -- q2
X -(152)
q
SO that x = - 0.644 for q = 0.910.
This value ofx corresponds to P/2e- = 1.71 (Eq. 145). Using Eqs. (134), (135)
and (141) with x = q = 0.91 leads to recalculation of the affinities and the value
of the effective radiant energy which is converted into chemical energy:
(hV)eff = 76.6 kJ.mol- 1
AAXp = 197.3 kJ.mol- 1
AcoF = -- 139.7 kJ.mol- 1
The difference between the incident radiant energy hv = 176.4 kJ.mol-1 and the
effective value (hv)eff represents the part of radiant energy dissipated into heat at
the antenna level. It can be interpreted as an adaptative control of the photosysterns when the light energy is provided in non-limiting conditions.
2) When the light energy transfer is the rate limiting process, the external
constraint now concerns the rate JATP. The f-function is then expressed as follows:
JATP = LAAAATP( 1 + qx) = K
(153)
The solution of Eqs. (148), (149) and (150) gives x = 0 which in turns leads to
P/2e- = 1.21, Aco F = 0 and (hv)eff = 216.4 kJ.mol-1. Obviously, the effective
radiant energy cannot be greater than the incident radiant energy value which
explains that for very limiting incident energy fluxes below the compensation
point, chemical energy is supplied by respiration.
6.1.3 Comparison of Experimental and Theoretical Values of P/2eThe experimental determination of the biomass composition enables one to
calculate the overall P/2e- ratio by the weighted sum of different P/2e- for the
synthesis of the fractions of cell material. Importantly, such calculations are only
feasible if a biochemically structured approach to metabolism is used. The
values of P/2e- obtained for the synthesis of the different parts of the biomass
are given in Table 2.
To test the applicability of the previous theoretical developments, the influence of three different cases of limitation on the biomass composition has been
investigated.
6.1.3.1 Light Energy Transfer Limitation
The cultures performed at a low light energy incident flux are considered
(Fo < 20W.m -2, non-limiting part of Figs. 10-12). As stated above, total