Overall assessment of Monodus
subterraneus cultivation and EPA production in outdoor helical and
bubble column reactors
C.
Lu, F.G. Acién Fernández,
E. Cañizares Guerrero, D.O. Hall, E.
Molina Grima-2002
Journal of Applied Phycology, 14(5):
331-342
Abstract
:
The outdoor production of Monodus subterraneus
was studied in bubble column and helical reactors, mainly analysing the
influence of dilution rate, air flow rate and solar irradiance on growth
rate and biochemical composition. Photoinhibition and photo-oxidation
phenomena were also analysed. The cultures were stressed at high solar
irradiance and dissolved oxygen concentrations. A clear relationship between
stress of the cultures and the fluorescence from PSII measurements was
observed, the Fv/Fm ratio being lower in the helical reactor than in the
bubble column. Growth rate and biomass productivity were both a function of
the average irradiance and the Fv/Fm ratio; maximum values of 0.040 h-1
and 0.54 g L-1 d-1 were measured. The influence of
photoinhibition and average irradiance was modelled, the model also fitting
the experimental data reported by another author. The chlorophyll content
hyperbolically decreased, whereas the carotenoid content decreased linearly
with the average irradiance. The higher the dilution rate the higher the
protein and carbohydrate content of the biomass, and the lower the lipid
content. The eicosapentaenoic acid (EPA) content ranged from 2.3 to 3.2%
d.wt, the higher the dilution rate, the lower EPA content, although the
higher the EPA proportion. Maximum EPA productivity was only 9 mg L-1
d-1, due to the stress to which the cultures were exposed.
(King's College
London, Division of Life Sciences, 150 Stamford Street, Waterloo London, SE1
8WA, UK)