Part B | 12.2
332 Part B Tools and Methods in Marine Biotechnology
Table 12.2 Photobioreactors (PBR)-tubular, plate/panel, stirred tank etc.
a
Sl Bioreactor
Marine strain and bioprocess
Reference
1
Flat plate PBR
CO 2 removal by green alga Chlorococcum littorale
Hu et al. [12.9]
2
Double-phase flat paneltype PBR
Microaerobic biohydrogen production by the nonsulfur
photosynthetic bacteria Rhodovulum sp.
Matsunaga et al. [12.10]
3
Flat alveolar panel PBR
(FAP-PBR), Green Wall
Panel PBR (GWP-PBR)
Oil production by algal strains (e.g., Nannochloropsis sp.)
Rodolfi et al. [12.11]
4
Tubular loop PBR a
Cultivation of red macroalga Porphyridium sp.
Merchuk et al. [12.12]
5
Tubular recycle PBR
Brown macroalga L. saccharina cultivation
Rorrer and Mullikin [12.13]
6
Stirred tank PBR
Biomass production of microalga Acrosiphonia coalita
Rorrer and Zhi [12.14]
7
Stirred tank PBR
Production of ˛-tocopherol by microalgae Euglena gracilis
Ogbonna et al. [12.15]
8
Three-stage serial
column-type PBR
(CPBR)
Spirulina sp. (cyanobacterium) for CO 2 biofixation through
photosynthesis
de Morais and Costa [12.16]
9
Laboratory-scale and
pilot-scale PBRs
Harvesting algal biomass of Euglena gracilis as potential animal
food source
Chae et al. [12.17]
10 Serpentine PBR and hybrid flow through-PBR
Biogas production by anaerobic digestion of microalga
P. tricornutum
Zamalloa et al. [12.18]
a Also compares the tabulated reactors with airlift and bubble-column reactors, restated in Table 12.4 with discussion in the Sect. 12.3
ALBR and BCBR
portantly, have significantly lower biomass productivity
than closed PBRs. The common design configurations
of the latter include plate/panel, tubular, stirred-tank
and vertical column (including airlift and bubble – column reactors). Tubular PBRs consist of an array of
straight, coiled, or looped transparent tubes through
which the culture is circulated by pump or by airlift
mechanism – the latter having the advantages of permitting exchange of CO 2 and O 2 between the liquid
medium and the aeration gas, minimizing shear damage
to the cells caused by mechanical pumping and achieving medium circulation without any moving parts. Increase in tube diameter (above 0:1 m) decreases the
surface/volume ratio and as culture density increases
with growth, the cells begins to shade one another
(self-shading effect) which results in decreasing volumetric biomass productivity. Again, excessive increase
in tube length causes accumulation of O 2 (produced
photosynthetically) which, when in excess of the air
saturation value, becomes inhibitory for photosynthesis (oxidative photoinhibition). Some common tubular
configurations are horizontal/serpentine, near horizontal, helical, conical, and inclined. In general, tubular
PBRs have a large illumination surface area but poor
mass transfer characteristics.
Flat-plate-type PBRs probably originated from
the laminar morphology of plant leaves which are
well-evolved natural solar collectors with high surface/volume ratio. They can be horizontal/vertical and
posses the advantage of high illumination surface area,
high photosynthetic efficiency, and lower accumulation of dissolved oxygen (than tubular PBRs). A tilted
flat-plate PBR (e.g., the flat inclined modular PBR –
FIMP) may be angled to ensure maximum exposure of
the culture to sunlight and facilitates change of light
path as and when required. This flexibility is often
crucial as individual photosynthetic microorganisms often have an optimum light path that is a compromise
between growth inhibition in innermost layers due to
insufficient lighting and self-shading, and photoinhibition of growth in outermost layers due to excessive
illumination. Stirred tank PBRs have also been used
for algal cultures but they are not as common as flat
plate/tubular-PBRs. Vertical column PBRs – mainly AL
and bubble column (BC) PBRs are discussed in the following section.
PBRs can be externally or internally illuminated.
External illumination may be natural (i. e., direct sunlight) or artificial (e.g., fluorescent lamps), internal
illumination is necessarily artificial. Optical fiber-based
internally illuminated PBRs have the advantage of heat
sterilizability and stability to withstand mechanical agitation stresses; however, low light delivery efficiency
(< 50%) is a concern.
Hu et al. [12.9] used a modified flat plate PBR
(1:4 L) to investigate CO 2 removal by an ultrahigh-cell-
332 Part B Tools and Methods in Marine Biotechnology
Table 12.2 Photobioreactors (PBR)-tubular, plate/panel, stirred tank etc.
a
Sl Bioreactor
Marine strain and bioprocess
Reference
1
Flat plate PBR
CO 2 removal by green alga Chlorococcum littorale
Hu et al. [12.9]
2
Double-phase flat paneltype PBR
Microaerobic biohydrogen production by the nonsulfur
photosynthetic bacteria Rhodovulum sp.
Matsunaga et al. [12.10]
3
Flat alveolar panel PBR
(FAP-PBR), Green Wall
Panel PBR (GWP-PBR)
Oil production by algal strains (e.g., Nannochloropsis sp.)
Rodolfi et al. [12.11]
4
Tubular loop PBR a
Cultivation of red macroalga Porphyridium sp.
Merchuk et al. [12.12]
5
Tubular recycle PBR
Brown macroalga L. saccharina cultivation
Rorrer and Mullikin [12.13]
6
Stirred tank PBR
Biomass production of microalga Acrosiphonia coalita
Rorrer and Zhi [12.14]
7
Stirred tank PBR
Production of ˛-tocopherol by microalgae Euglena gracilis
Ogbonna et al. [12.15]
8
Three-stage serial
column-type PBR
(CPBR)
Spirulina sp. (cyanobacterium) for CO 2 biofixation through
photosynthesis
de Morais and Costa [12.16]
9
Laboratory-scale and
pilot-scale PBRs
Harvesting algal biomass of Euglena gracilis as potential animal
food source
Chae et al. [12.17]
10 Serpentine PBR and hybrid flow through-PBR
Biogas production by anaerobic digestion of microalga
P. tricornutum
Zamalloa et al. [12.18]
a Also compares the tabulated reactors with airlift and bubble-column reactors, restated in Table 12.4 with discussion in the Sect. 12.3
ALBR and BCBR
portantly, have significantly lower biomass productivity
than closed PBRs. The common design configurations
of the latter include plate/panel, tubular, stirred-tank
and vertical column (including airlift and bubble – column reactors). Tubular PBRs consist of an array of
straight, coiled, or looped transparent tubes through
which the culture is circulated by pump or by airlift
mechanism – the latter having the advantages of permitting exchange of CO 2 and O 2 between the liquid
medium and the aeration gas, minimizing shear damage
to the cells caused by mechanical pumping and achieving medium circulation without any moving parts. Increase in tube diameter (above 0:1 m) decreases the
surface/volume ratio and as culture density increases
with growth, the cells begins to shade one another
(self-shading effect) which results in decreasing volumetric biomass productivity. Again, excessive increase
in tube length causes accumulation of O 2 (produced
photosynthetically) which, when in excess of the air
saturation value, becomes inhibitory for photosynthesis (oxidative photoinhibition). Some common tubular
configurations are horizontal/serpentine, near horizontal, helical, conical, and inclined. In general, tubular
PBRs have a large illumination surface area but poor
mass transfer characteristics.
Flat-plate-type PBRs probably originated from
the laminar morphology of plant leaves which are
well-evolved natural solar collectors with high surface/volume ratio. They can be horizontal/vertical and
posses the advantage of high illumination surface area,
high photosynthetic efficiency, and lower accumulation of dissolved oxygen (than tubular PBRs). A tilted
flat-plate PBR (e.g., the flat inclined modular PBR –
FIMP) may be angled to ensure maximum exposure of
the culture to sunlight and facilitates change of light
path as and when required. This flexibility is often
crucial as individual photosynthetic microorganisms often have an optimum light path that is a compromise
between growth inhibition in innermost layers due to
insufficient lighting and self-shading, and photoinhibition of growth in outermost layers due to excessive
illumination. Stirred tank PBRs have also been used
for algal cultures but they are not as common as flat
plate/tubular-PBRs. Vertical column PBRs – mainly AL
and bubble column (BC) PBRs are discussed in the following section.
PBRs can be externally or internally illuminated.
External illumination may be natural (i. e., direct sunlight) or artificial (e.g., fluorescent lamps), internal
illumination is necessarily artificial. Optical fiber-based
internally illuminated PBRs have the advantage of heat
sterilizability and stability to withstand mechanical agitation stresses; however, low light delivery efficiency
(< 50%) is a concern.
Hu et al. [12.9] used a modified flat plate PBR
(1:4 L) to investigate CO 2 removal by an ultrahigh-cell-