synthetic forms are less expensive than the naturals, microalgae carotenoids have
the advantage of supplying natural isomers in their natural ratio (Guil-Guerrero
et al. 2004; Waldenstedt et al. 2003). D. Salina is the microorganism most used for
the production of b-carotene due to the possibilities of reaching 14% in dry weight,
and its cultivation process is easy to implement (can be realized in raceway systems) (Spolaore et al. 2006). Due to the photosynthesis capacity, these microalgae
are able to incorporate stable isotopes like
13 C,
15 N y
2 H from inorganic chemical
compounds such as
13 CO 2 ,
15 NO 3 ,
2 H 2 O that are used for protein quantification
(Spolaore et al. 2006).
In recent years, due to oil crisis the studies are concentrated in the obtaining and
use of microalgae lipids for energy generation, transforming it to biofuels, mainly to
biodiesel (Chisti 2007). From this perspective, the microalgae cultivation has been
focused on the biotechnological point of view, analyzing their implementation in
biorefineries.
2 Process of Culture
2.1 Autotrophic Growth
Microalgae can implement oxygenic photosynthesis and carbon dioxide fixation
through Calvin cycle. In other words, they can capture energy from light and use
carbon dioxide like carbon source (Yang et al. 2000). Therefore, microalgae have
the ability to mitigate carbon dioxide emissions that are produced by industry,
generating high-value products (Chen et al. 2011).
2.1.1 Open Ponds Systems
The open ponds systems is the most commonly used configuration for microalgae
production, due that these cultivation methods are economically feasible for
high-scale biomass production (Safi et al. 2014). The cells grow under sunlight and
carbon dioxide supply (Slegers et al. 2013).
These systems have some limitations due to a strict environmental control with
the aim to avoid biological contaminations like bacteria or not desired species, also
neutralizing pollution in the systems and water evaporation (Safi et al. 2014).
2.1.2 Photobioreactors
Although the initial investment is the highest in comparison to open ponds systems,
photobioreactors permit a better contamination control, as well as better use and
control of light intensity, carbon dioxide, and nutrients supply (Sforza et al. 2012).
9 Biofuels from Microalgae: Energy and Exergy Analysis for the …
183
the advantage of supplying natural isomers in their natural ratio (Guil-Guerrero
et al. 2004; Waldenstedt et al. 2003). D. Salina is the microorganism most used for
the production of b-carotene due to the possibilities of reaching 14% in dry weight,
and its cultivation process is easy to implement (can be realized in raceway systems) (Spolaore et al. 2006). Due to the photosynthesis capacity, these microalgae
are able to incorporate stable isotopes like
13 C,
15 N y
2 H from inorganic chemical
compounds such as
13 CO 2 ,
15 NO 3 ,
2 H 2 O that are used for protein quantification
(Spolaore et al. 2006).
In recent years, due to oil crisis the studies are concentrated in the obtaining and
use of microalgae lipids for energy generation, transforming it to biofuels, mainly to
biodiesel (Chisti 2007). From this perspective, the microalgae cultivation has been
focused on the biotechnological point of view, analyzing their implementation in
biorefineries.
2 Process of Culture
2.1 Autotrophic Growth
Microalgae can implement oxygenic photosynthesis and carbon dioxide fixation
through Calvin cycle. In other words, they can capture energy from light and use
carbon dioxide like carbon source (Yang et al. 2000). Therefore, microalgae have
the ability to mitigate carbon dioxide emissions that are produced by industry,
generating high-value products (Chen et al. 2011).
2.1.1 Open Ponds Systems
The open ponds systems is the most commonly used configuration for microalgae
production, due that these cultivation methods are economically feasible for
high-scale biomass production (Safi et al. 2014). The cells grow under sunlight and
carbon dioxide supply (Slegers et al. 2013).
These systems have some limitations due to a strict environmental control with
the aim to avoid biological contaminations like bacteria or not desired species, also
neutralizing pollution in the systems and water evaporation (Safi et al. 2014).
2.1.2 Photobioreactors
Although the initial investment is the highest in comparison to open ponds systems,
photobioreactors permit a better contamination control, as well as better use and
control of light intensity, carbon dioxide, and nutrients supply (Sforza et al. 2012).
9 Biofuels from Microalgae: Energy and Exergy Analysis for the …
183