and (iv) the biofuel generated must present a quality standard required by the
legislation and in quantity that makes the process economically viable.
2.3.5 Commercial Applications of Heterotrophic Bioreactors
The commercial production of microalgae via heterotrophic metabolism has been
made by the Solazyme Inc., in Moema, São Paulo (Brazil). Solazyme’s technology
enables it to successfully convert a range of low-cost plant-based sugars into biofuels. The biofuels that this company has produced and tested are biodiesel
(SoladieselBD
® ), renewable diesel (SoladieselRD
® ), aviation turbine fuel
(Solajet™), and renewable jet fuel. Furthermore, Solazyme is producing renewable
oils for the chemicals, nutrition and skin and personal care space utilizing today’s
existing industrial scale fermentation capacity.
3 Small-Scale Photobioreactors
3.1 Vertical Photobioreactors
Vertical reactors were among the first algal mass culture systems described in the
literature (Cook 1950). These systems are compact, user-friendly bioreactors with a
high ratio of surface area/volume, low contamination risk, and high biomass productivity. However, at present, these systems are not used as photobioreactors,
except for investigational purposes, due to their difficult of scaling-up (Mirón et al.
1999).
Vertical photobioreactors consist of vertical tubes constructed with a transparent
material (polyethylene or glass tubes) to allow the penetration of light. An air
diffuser is located at the bottom of the reactor, where the sparged gas is converted
into tiny bubbles. This sparging with gas mixture provides the constant agitation of
the medium, mass transfer of CO 2 and also removes O 2 produced during photosynthesis. Based on their mode of liquid flow, vertical tubular photobioreactors can
be divided into bubble column and airlift PBRs (Singh and Sharma 2012; Chang
et al. 2017).
Bubble column photobioreactors are cylindrical vessel with height greater than
twice the diameter, simply agitated by bubbling CO 2 and air from a sparger at the
photobioreactor bottom without any special internal constructions and completely
lack any moving parts (Singh and Sharma 2012; Koller 2015).
Airlift photobioreactors are cylindrical tubes with two interconnecting zones.
One of the zones is called riser where gas mixture is sparged, whereas the other
zone, the downcomer, does not receive the gas. The system can be with internal
loop and external loop. In the first option, regions are separated either by a draft
18
M. M. Maroneze and M. I. Queiroz
legislation and in quantity that makes the process economically viable.
2.3.5 Commercial Applications of Heterotrophic Bioreactors
The commercial production of microalgae via heterotrophic metabolism has been
made by the Solazyme Inc., in Moema, São Paulo (Brazil). Solazyme’s technology
enables it to successfully convert a range of low-cost plant-based sugars into biofuels. The biofuels that this company has produced and tested are biodiesel
(SoladieselBD
® ), renewable diesel (SoladieselRD
® ), aviation turbine fuel
(Solajet™), and renewable jet fuel. Furthermore, Solazyme is producing renewable
oils for the chemicals, nutrition and skin and personal care space utilizing today’s
existing industrial scale fermentation capacity.
3 Small-Scale Photobioreactors
3.1 Vertical Photobioreactors
Vertical reactors were among the first algal mass culture systems described in the
literature (Cook 1950). These systems are compact, user-friendly bioreactors with a
high ratio of surface area/volume, low contamination risk, and high biomass productivity. However, at present, these systems are not used as photobioreactors,
except for investigational purposes, due to their difficult of scaling-up (Mirón et al.
1999).
Vertical photobioreactors consist of vertical tubes constructed with a transparent
material (polyethylene or glass tubes) to allow the penetration of light. An air
diffuser is located at the bottom of the reactor, where the sparged gas is converted
into tiny bubbles. This sparging with gas mixture provides the constant agitation of
the medium, mass transfer of CO 2 and also removes O 2 produced during photosynthesis. Based on their mode of liquid flow, vertical tubular photobioreactors can
be divided into bubble column and airlift PBRs (Singh and Sharma 2012; Chang
et al. 2017).
Bubble column photobioreactors are cylindrical vessel with height greater than
twice the diameter, simply agitated by bubbling CO 2 and air from a sparger at the
photobioreactor bottom without any special internal constructions and completely
lack any moving parts (Singh and Sharma 2012; Koller 2015).
Airlift photobioreactors are cylindrical tubes with two interconnecting zones.
One of the zones is called riser where gas mixture is sparged, whereas the other
zone, the downcomer, does not receive the gas. The system can be with internal
loop and external loop. In the first option, regions are separated either by a draft
18
M. M. Maroneze and M. I. Queiroz