two types of culture can be used: turbidostat and chemostat culture (Ghasemi et al.
2012). In the turbidostat culture, when the density reaches a preset level, fresh
medium is added to the culture as the cells continue to divide and grow. In the
chemostat culture, a slow but steady flow of fresh medium is continually introduced
into the culture while excess culture overflows and collected. Two types of reactors
have been developed to cultivate algae: open system (such as raceway ponds) and
closed system (such as photobioreactors) (Brennan and Owende 2010; Ghasemi
et al. 2012; Narala et al. 2016).
1.3.1.1 Open Pond Systems
Open pond system is the oldest system and can be categorized into natural and
artificial water ponds or containers (Jimenez et al. 2003). Raceway ponds are the
most commonly used artificial system for mass cultivation of microalgae. It is
usually 0.2 and 0.5 m deep in length to thousands of meters and consists of a pond
in the shape of a raceway. The raceway ponds mimics the way of algae to grow in
their natural environment in which the liquid is circulated around the pond by a
paddle wheel to stabilize algae growth and productivity. Raceway ponds are usually
made from poured concrete and compacted into the earth with white plastic liner.
Due to scalability and low cost of building, they are the most popular artificial
cultivation system (Singh et al. 2011). In open pond systems, algal medium and their
nutrients are introduced in front of the paddle wheel and circulated using the loop for
Table 1.1 Oil content of microalgae (Sajjadi et al. 2018)
S. No.
Species
Oil content
References
1
Dunaliella primolecta
23%
Sajjadi et al. (2018)
2
Dunaliella salina
6–25%
Sajjadi et al. (2018)
3
Nannochloris sp.
25-56%
Vasudevan and Briggs (2008)
4
Chaetoceros muelleri
13–24%
Rodríguez et al. (2012)
5
Scenedesmus obliquus
30–50%
Caprio et al. (2015)
6
Chlamydomonas sp.
22.7%
Jeon et al. (2015)
7
Parietochloris incisa
62%
Sajjadi et al. (2018)
8
Tetraselmis tetrathele
25–30%
Sajjadi et al. (2018)
9
Neochloris oleoabundans
35–65%
Vasudevan and Briggs (2008)
10
Chlorella sp.
28–53%
Vasudevan and Briggs (2008)
11
Nostoc commune
22%
Sajjadi et al. (2018)
12
Spirulina Platensis
4–11%
Sajjadi et al. (2018)
13
Synechocystis sp.
11%
Abdelkhaalek et al. (2016)
14
Emiliania huxleyi
43.8%
Sajjadi et al. (2018)
15
Heterosigma akashiwo
43%
Stewart (2014)
16
Chroomonas salina
12–14.5%
Sajjadi et al. (2018)
17
Porphyridium cruentum
9–14%
Sajjadi et al. (2018)
18
Mesotaenium sp.
19–35%
Sajjadi et al. (2018)
19
Schizochytrium sp.
50–77%
Sun et al. (2014)
1 Algal Biofuel: A Sustainable Approach for Fuel of Future Generation
7
2012). In the turbidostat culture, when the density reaches a preset level, fresh
medium is added to the culture as the cells continue to divide and grow. In the
chemostat culture, a slow but steady flow of fresh medium is continually introduced
into the culture while excess culture overflows and collected. Two types of reactors
have been developed to cultivate algae: open system (such as raceway ponds) and
closed system (such as photobioreactors) (Brennan and Owende 2010; Ghasemi
et al. 2012; Narala et al. 2016).
1.3.1.1 Open Pond Systems
Open pond system is the oldest system and can be categorized into natural and
artificial water ponds or containers (Jimenez et al. 2003). Raceway ponds are the
most commonly used artificial system for mass cultivation of microalgae. It is
usually 0.2 and 0.5 m deep in length to thousands of meters and consists of a pond
in the shape of a raceway. The raceway ponds mimics the way of algae to grow in
their natural environment in which the liquid is circulated around the pond by a
paddle wheel to stabilize algae growth and productivity. Raceway ponds are usually
made from poured concrete and compacted into the earth with white plastic liner.
Due to scalability and low cost of building, they are the most popular artificial
cultivation system (Singh et al. 2011). In open pond systems, algal medium and their
nutrients are introduced in front of the paddle wheel and circulated using the loop for
Table 1.1 Oil content of microalgae (Sajjadi et al. 2018)
S. No.
Species
Oil content
References
1
Dunaliella primolecta
23%
Sajjadi et al. (2018)
2
Dunaliella salina
6–25%
Sajjadi et al. (2018)
3
Nannochloris sp.
25-56%
Vasudevan and Briggs (2008)
4
Chaetoceros muelleri
13–24%
Rodríguez et al. (2012)
5
Scenedesmus obliquus
30–50%
Caprio et al. (2015)
6
Chlamydomonas sp.
22.7%
Jeon et al. (2015)
7
Parietochloris incisa
62%
Sajjadi et al. (2018)
8
Tetraselmis tetrathele
25–30%
Sajjadi et al. (2018)
9
Neochloris oleoabundans
35–65%
Vasudevan and Briggs (2008)
10
Chlorella sp.
28–53%
Vasudevan and Briggs (2008)
11
Nostoc commune
22%
Sajjadi et al. (2018)
12
Spirulina Platensis
4–11%
Sajjadi et al. (2018)
13
Synechocystis sp.
11%
Abdelkhaalek et al. (2016)
14
Emiliania huxleyi
43.8%
Sajjadi et al. (2018)
15
Heterosigma akashiwo
43%
Stewart (2014)
16
Chroomonas salina
12–14.5%
Sajjadi et al. (2018)
17
Porphyridium cruentum
9–14%
Sajjadi et al. (2018)
18
Mesotaenium sp.
19–35%
Sajjadi et al. (2018)
19
Schizochytrium sp.
50–77%
Sun et al. (2014)
1 Algal Biofuel: A Sustainable Approach for Fuel of Future Generation
7