Additionally, these systems can operate in parallel in wastewater treatment, when
they are used as a source of carbon and nutrients for algal growing. On the other
hand, to produce light-induced metabolites and high-value products intended for
human consumption, a closed PBR is more advisable (Li et al. 2014; Chang et al.
2017).
The characteristics of the microalgae strain that will be used must also be
considered at the moment of the choice. Mainly in terms of adaptability and tolerance under outdoor conditions and shear forces and oxygen buildup generated by
PBRs. In open ponds, strains must be able to compete with other microorganisms
for nutrients and must have the ability to tolerate photoperiods and climate changes.
In the case of closed photobioreactors, the strains must withstand strong shear
forces generated by pumping or aeration and must be able to tolerate a possible
excess of oxygen in the system (Brennan and Owende 2010; Chang et al. 2017).
When a biofuel is the target product, the most important issue is the cost of the
biomass which will be processed to yield the fuel. For this, the systems must
present a high kinetic performance at large-scale production. It is known that closed
systems are significantly more efficient in biomass production compared with open
systems. At the same time, most closed systems have a difficult and expensive
scaling-up, and open systems can be scaled up easily and inexpensively to
accommodate larger production rates. So, the choice of cultivation system must be
based on the best trade-off between biomass productivity and production cost
(Chang et al. 2017).
Table 7 Advantages and limitations of microalgae cultivation systems
Cultivation
type
Cultivation system
Advantages
Limitations
Commercial
Raceway ponds
– Low investment
– Low power
consumption
– Economical
– Easy to clean
– Easy maintenance
– Require large area of
land
– Cultures are easily
contaminated
– Low productivity
– Limited to a few
microalgal strains
– Little control of
culture conditions
– Evaporation
– Small illumination
surface area
Horizontal tubular
photobioreactors
– High productivity
– Large illumination
surface area
– Suitable for outdoor
cultures
– Relatively cheap
– Large land area
demand
– Poor mass transfer
– Photoinhibition
(continued)
26
M. M. Maroneze and M. I. Queiroz
they are used as a source of carbon and nutrients for algal growing. On the other
hand, to produce light-induced metabolites and high-value products intended for
human consumption, a closed PBR is more advisable (Li et al. 2014; Chang et al.
2017).
The characteristics of the microalgae strain that will be used must also be
considered at the moment of the choice. Mainly in terms of adaptability and tolerance under outdoor conditions and shear forces and oxygen buildup generated by
PBRs. In open ponds, strains must be able to compete with other microorganisms
for nutrients and must have the ability to tolerate photoperiods and climate changes.
In the case of closed photobioreactors, the strains must withstand strong shear
forces generated by pumping or aeration and must be able to tolerate a possible
excess of oxygen in the system (Brennan and Owende 2010; Chang et al. 2017).
When a biofuel is the target product, the most important issue is the cost of the
biomass which will be processed to yield the fuel. For this, the systems must
present a high kinetic performance at large-scale production. It is known that closed
systems are significantly more efficient in biomass production compared with open
systems. At the same time, most closed systems have a difficult and expensive
scaling-up, and open systems can be scaled up easily and inexpensively to
accommodate larger production rates. So, the choice of cultivation system must be
based on the best trade-off between biomass productivity and production cost
(Chang et al. 2017).
Table 7 Advantages and limitations of microalgae cultivation systems
Cultivation
type
Cultivation system
Advantages
Limitations
Commercial
Raceway ponds
– Low investment
– Low power
consumption
– Economical
– Easy to clean
– Easy maintenance
– Require large area of
land
– Cultures are easily
contaminated
– Low productivity
– Limited to a few
microalgal strains
– Little control of
culture conditions
– Evaporation
– Small illumination
surface area
Horizontal tubular
photobioreactors
– High productivity
– Large illumination
surface area
– Suitable for outdoor
cultures
– Relatively cheap
– Large land area
demand
– Poor mass transfer
– Photoinhibition
(continued)
26
M. M. Maroneze and M. I. Queiroz