Part B | 12.3
342 Part B Tools and Methods in Marine Biotechnology
metered through calibrated flow meters, and sterilized
using membrane filters (pore size 0:22 m) before entering the reactor (at an aeration rate of 0:2 vvm). The
bottom of the bioreactor was filled with a porous quartz
sieve (diameter 10 mm), which dispersed the airstream.
The cultures were illuminated from two sides with cool
white fluorescent lamps under 14 h/10 h light/dark cycle. CO 2 was supplemented in air only during the light
phase.
Seven-day-old cell cultures from the BCBR were
concentrated by centrifugation and transferred into
a 500 mL cylindrical glass bioreactor. They were subjected to the dark anaerobic induction of hydrogenase
at 25
ı C for 12 h, after continuous flushing for 10 min
with N 2 (99:9% purity) through the culture to purge O 2 .
15 1M CCCP (carbonylcyanide m-chlorophenylhydrazone) was then added, and the culture further incubated
in darkness for 20 min, before initiating photobiological H 2 production under continuous illumination. It was
demonstrated in this study that the marine green alga P.
subcordiformis could efficiently convert CO 2 into intracellular starch through photosynthesis and improve H 2
photoproduction through increased accumulation of intracellular starch under CO 2 supplementation in an air
bubble column PBR.
Huang and Rorrer [12.31] investigated the optimal
values of cultivation temperature and diurnal photoperiod for the phototrophic growth of a microplantlet suspension culture derived from the macrophytic marine
red alga Agardhiella subulata in a BC-PBR. Cultivation
temperature and light delivery are two crucial process
variables in the design of PBRs for culturing marine
microalgae (seaweed). The latter has two components,
viz., the light flux intensity and the diurnal photoperiod,
i. e., the light/dark (L/D) illumination cycle in 24 h. It
was observed in this study that biomass production increased with increasing photoperiod at low fractional
photoperiods (Ä 10 W 14 L/D) but at high fractional photoperiods approaching continuous illumination ( 20 W
4 L/D) biomass production practically stopped, presumably due to photodamage that inhibits growth). The
optimal photoperiod for biomass production was found
to be 16 W 8 L/D.
An externally illuminated BC-PBR (same working principle as that used in Zhi and Rorrer [12.32],
cited immediately afterward) (effective cultivation volume 250 mL) consisted of a 12:7 cm straight section
(diameter 4:5 cm) and a 15:2 cm conical riser section
(inner diameter 1:3 cm at the base). The small vessel diameter minimized light attenuation through the
microplantlet suspension. Air was metered, humidified in a bubbler, sterilized through an autoclaved filter
(0:2 m pore size), and then introduced into the base of
the riser section through a glass frit (diameter 1:3 cm,
pore size 4060 m). The liquid suspension culture in
the vessel was uniformly agitated and aerated by rising air bubbles (nominal diameter 1:0 mm). Ambient
CO 2 in the aeration gas (normally 350 ppm) served as
the carbon source for photosynthetic biomass growth.
The illumination stage consisted of two 6:0 W coolwhite fluorescent lamps vertically mounted on opposing
sides of the glass vessel. A referencing plate set the
distance between each lamp and vessel wall to deliver the desired incident light flux intensity to the
culture and a programmable timer set the photoperiod
for each lamp. The PBR was maintained at 24
ı C within
a temperature-controlled room. Two identical BC-PBRs
described above were operated in parallel, each inoculated with microplantets from a common inoculum
source.
Zhi and Rorrer [12.32] demonstrated the feasibility
of the photolithotrophic cultivation of a cell suspension
culture derived from the microscopic, filamentous gametophytic life phase of the brown marine macroalga
L. saccharina in an illuminated BC-PBR, at 13
ı C using CO 2 in air as the sole carbon source for growth. Two
illuminated glass BCBRs were employed with effective
cultivation volumes of 280 and 900 mL, respectively.
Each BCBR system, comprising the bioreactor assembly, aeration unit, and illumination arrangement, was
housed in a low-temperature incubator fitted with two
auxiliary convection fans to maintain uniform temperature, and fresh air was supplied to maintain a constant
ambient CO 2 concentration in the incubator gas space
(vol. 500 L). Four identical 280 mL bioreactor systems and two 900 mL bioreactor systems were used
for batch experiments under different conditions using
a common inoculum. The bioreactors of a given volume were all located within the same low temperature
incubator.
The 280 mL BCBR (Fig. 12.15) consisted of
a 12:70 cm straight section (I.D. 4:45 cm) and
a 15:24 cm conical riser section (base I.D. 1:27 cm),
and was sealed to the head plate with two G-rings,
one above and one below the flange of the glass body.
The head plate had two ports, for the sampling assembly and for air outlet, respectively, with the latter
connected to a sterilizing filter (0:2 m). Agitation
was provided by rising air bubbles introduced into
the reactor base through the sparger assembly. Ambient air from an aquarium pump was metered, filter –
sterilized (0:2 m), and then bubbled through a ster-
342 Part B Tools and Methods in Marine Biotechnology
metered through calibrated flow meters, and sterilized
using membrane filters (pore size 0:22 m) before entering the reactor (at an aeration rate of 0:2 vvm). The
bottom of the bioreactor was filled with a porous quartz
sieve (diameter 10 mm), which dispersed the airstream.
The cultures were illuminated from two sides with cool
white fluorescent lamps under 14 h/10 h light/dark cycle. CO 2 was supplemented in air only during the light
phase.
Seven-day-old cell cultures from the BCBR were
concentrated by centrifugation and transferred into
a 500 mL cylindrical glass bioreactor. They were subjected to the dark anaerobic induction of hydrogenase
at 25
ı C for 12 h, after continuous flushing for 10 min
with N 2 (99:9% purity) through the culture to purge O 2 .
15 1M CCCP (carbonylcyanide m-chlorophenylhydrazone) was then added, and the culture further incubated
in darkness for 20 min, before initiating photobiological H 2 production under continuous illumination. It was
demonstrated in this study that the marine green alga P.
subcordiformis could efficiently convert CO 2 into intracellular starch through photosynthesis and improve H 2
photoproduction through increased accumulation of intracellular starch under CO 2 supplementation in an air
bubble column PBR.
Huang and Rorrer [12.31] investigated the optimal
values of cultivation temperature and diurnal photoperiod for the phototrophic growth of a microplantlet suspension culture derived from the macrophytic marine
red alga Agardhiella subulata in a BC-PBR. Cultivation
temperature and light delivery are two crucial process
variables in the design of PBRs for culturing marine
microalgae (seaweed). The latter has two components,
viz., the light flux intensity and the diurnal photoperiod,
i. e., the light/dark (L/D) illumination cycle in 24 h. It
was observed in this study that biomass production increased with increasing photoperiod at low fractional
photoperiods (Ä 10 W 14 L/D) but at high fractional photoperiods approaching continuous illumination ( 20 W
4 L/D) biomass production practically stopped, presumably due to photodamage that inhibits growth). The
optimal photoperiod for biomass production was found
to be 16 W 8 L/D.
An externally illuminated BC-PBR (same working principle as that used in Zhi and Rorrer [12.32],
cited immediately afterward) (effective cultivation volume 250 mL) consisted of a 12:7 cm straight section
(diameter 4:5 cm) and a 15:2 cm conical riser section
(inner diameter 1:3 cm at the base). The small vessel diameter minimized light attenuation through the
microplantlet suspension. Air was metered, humidified in a bubbler, sterilized through an autoclaved filter
(0:2 m pore size), and then introduced into the base of
the riser section through a glass frit (diameter 1:3 cm,
pore size 4060 m). The liquid suspension culture in
the vessel was uniformly agitated and aerated by rising air bubbles (nominal diameter 1:0 mm). Ambient
CO 2 in the aeration gas (normally 350 ppm) served as
the carbon source for photosynthetic biomass growth.
The illumination stage consisted of two 6:0 W coolwhite fluorescent lamps vertically mounted on opposing
sides of the glass vessel. A referencing plate set the
distance between each lamp and vessel wall to deliver the desired incident light flux intensity to the
culture and a programmable timer set the photoperiod
for each lamp. The PBR was maintained at 24
ı C within
a temperature-controlled room. Two identical BC-PBRs
described above were operated in parallel, each inoculated with microplantets from a common inoculum
source.
Zhi and Rorrer [12.32] demonstrated the feasibility
of the photolithotrophic cultivation of a cell suspension
culture derived from the microscopic, filamentous gametophytic life phase of the brown marine macroalga
L. saccharina in an illuminated BC-PBR, at 13
ı C using CO 2 in air as the sole carbon source for growth. Two
illuminated glass BCBRs were employed with effective
cultivation volumes of 280 and 900 mL, respectively.
Each BCBR system, comprising the bioreactor assembly, aeration unit, and illumination arrangement, was
housed in a low-temperature incubator fitted with two
auxiliary convection fans to maintain uniform temperature, and fresh air was supplied to maintain a constant
ambient CO 2 concentration in the incubator gas space
(vol. 500 L). Four identical 280 mL bioreactor systems and two 900 mL bioreactor systems were used
for batch experiments under different conditions using
a common inoculum. The bioreactors of a given volume were all located within the same low temperature
incubator.
The 280 mL BCBR (Fig. 12.15) consisted of
a 12:70 cm straight section (I.D. 4:45 cm) and
a 15:24 cm conical riser section (base I.D. 1:27 cm),
and was sealed to the head plate with two G-rings,
one above and one below the flange of the glass body.
The head plate had two ports, for the sampling assembly and for air outlet, respectively, with the latter
connected to a sterilizing filter (0:2 m). Agitation
was provided by rising air bubbles introduced into
the reactor base through the sparger assembly. Ambient air from an aquarium pump was metered, filter –
sterilized (0:2 m), and then bubbled through a ster-