research papers indicate a strong interest in microalgae biorefinery looking for
industrial-scale applications (Konur 2011; Mohan et al. 2016a, b; Xu and Boeing
2013; Zhu et al. 2016). The microalgae cultivation has high areal productivity, the
possibility to grow in nonarable land, or wastewater used as nutrient source. From
the biomass obtained, a spectrum of marketable products can be obtained, such as
pigments, proteins, lipids, carbohydrates, vitamins, and antioxidants for applications like feed, food, polymers, pharmaceuticals, cosmetics, and biofuels
(Borowitzka 2013; Budzianowski 2017; Suganya et al. 2016). Although microalgae
biofuels are technically feasible, they remain strongly dependent on government
subsidies and oil price, which make them economically nonviable for now (Wijffels
and Barbosa 2010); therefore, primary strategies for bioenergy production from
algae will need to rely on a multiproduct biorefinery approach (Laurens et al.
2017a). The CO 2 capture and the use of wastewater as nutrient source for
microalgae growth combined with the production of high-value-added products and
bioenergy make microalgae biorefinery potentially profitable.
2 Products Portfolio from Microalgae and Applications
The main goal of the biorefinery is to integrate the production of bioenergy
(commodities: low-value high-volume products) and other chemicals (high-value
low-volume products) to optimize the use of biomass resources by reducing wastes
while maximizing profitability and benefits (Demibras 2009). Budzianowski (2017)
categorized the high-value low-volume bioproducts from biorefineries into six
groups: biopharmaceuticals, biocosmetics, bionutrients, biochemicals, biofertilizers,
and biomaterials. All of them and biofuels can be obtained from microalgae (Chew
et al. 2017; Milledge 2011). The microalgae products are reviewed in this section
and summarized in Table 1 and Fig. 1.
Biopharmaceuticals: Microalgae are a source of many potential new drugs and
bioactive molecules for health industry (Abd El Baky and El-Baroty 2013;
Borowitzka 1995; Deniz et al. 2017; Mimouni et al. 2012). According to the
number of patent publications, currently, biopharmaceutics is one of the most
important innovation areas under development (Chilton et al. 2016). The bioactive
molecules include applications, such as antioxidant, anti-inflammatory, antitumor,
anticancer, antimicrobial, antiviral, and antiallergic agents along with other pharmaceutical properties (Deniz et al. 2017). Pigments, such as carotenoids (b-carotene
and astaxanthin), phycobiliproteins (phycocyanin), and some polysaccharides or
phenolic derivatives exhibit antioxidant and anti-inflammatory activities.
Phycobilins have anti-inflammatory, antiallergic, antioxidant, and anticancer
activities (Kim et al. 2016). Polyunsaturated fatty acids (PUFAs) are also of interest
for human welfare, and there is a recent market of 11.5 billion dollars (Béligon et al.
2016). Molecules used for anticancer or antitumor effects include polysaccharides
(carrageenan and fucoidan), PUFAs (eicosapentaenoic acid, EPA; or
5 Microalgae Biorefineries for Energy …
91
industrial-scale applications (Konur 2011; Mohan et al. 2016a, b; Xu and Boeing
2013; Zhu et al. 2016). The microalgae cultivation has high areal productivity, the
possibility to grow in nonarable land, or wastewater used as nutrient source. From
the biomass obtained, a spectrum of marketable products can be obtained, such as
pigments, proteins, lipids, carbohydrates, vitamins, and antioxidants for applications like feed, food, polymers, pharmaceuticals, cosmetics, and biofuels
(Borowitzka 2013; Budzianowski 2017; Suganya et al. 2016). Although microalgae
biofuels are technically feasible, they remain strongly dependent on government
subsidies and oil price, which make them economically nonviable for now (Wijffels
and Barbosa 2010); therefore, primary strategies for bioenergy production from
algae will need to rely on a multiproduct biorefinery approach (Laurens et al.
2017a). The CO 2 capture and the use of wastewater as nutrient source for
microalgae growth combined with the production of high-value-added products and
bioenergy make microalgae biorefinery potentially profitable.
2 Products Portfolio from Microalgae and Applications
The main goal of the biorefinery is to integrate the production of bioenergy
(commodities: low-value high-volume products) and other chemicals (high-value
low-volume products) to optimize the use of biomass resources by reducing wastes
while maximizing profitability and benefits (Demibras 2009). Budzianowski (2017)
categorized the high-value low-volume bioproducts from biorefineries into six
groups: biopharmaceuticals, biocosmetics, bionutrients, biochemicals, biofertilizers,
and biomaterials. All of them and biofuels can be obtained from microalgae (Chew
et al. 2017; Milledge 2011). The microalgae products are reviewed in this section
and summarized in Table 1 and Fig. 1.
Biopharmaceuticals: Microalgae are a source of many potential new drugs and
bioactive molecules for health industry (Abd El Baky and El-Baroty 2013;
Borowitzka 1995; Deniz et al. 2017; Mimouni et al. 2012). According to the
number of patent publications, currently, biopharmaceutics is one of the most
important innovation areas under development (Chilton et al. 2016). The bioactive
molecules include applications, such as antioxidant, anti-inflammatory, antitumor,
anticancer, antimicrobial, antiviral, and antiallergic agents along with other pharmaceutical properties (Deniz et al. 2017). Pigments, such as carotenoids (b-carotene
and astaxanthin), phycobiliproteins (phycocyanin), and some polysaccharides or
phenolic derivatives exhibit antioxidant and anti-inflammatory activities.
Phycobilins have anti-inflammatory, antiallergic, antioxidant, and anticancer
activities (Kim et al. 2016). Polyunsaturated fatty acids (PUFAs) are also of interest
for human welfare, and there is a recent market of 11.5 billion dollars (Béligon et al.
2016). Molecules used for anticancer or antitumor effects include polysaccharides
(carrageenan and fucoidan), PUFAs (eicosapentaenoic acid, EPA; or
5 Microalgae Biorefineries for Energy …
91