post-harvesting technology, (5) methods and sequence of extraction of coproducts/
processing the whole biomass/the pre-extracted product to final products, (6) process integration of streams and recycling of materials, reducing wastes, and finally
(7) a life cycle analysis. In the case of high-value products, Eppink et al. (2017)
suggested specific recommendations about harvesting, cell disruption, and extraction methods. They indicated the need to know the composition and strength of the
cell wall, and localization of the target compound in the cytoplasm, as well as to
select moderated harvesting methods and mild cell disruption, removing first the
cell wall and after, the organelle disruption. The next step is the selective separation
of hydrophobic (lipids, pigments) and hydrophilic (proteins, carbohydrates) fractions while keeping full functionality and finally, fractioning the hydrophilic and
hydrophobic component mixtures to recover target compounds for different market
applications. The final step for the implementation of a biorefinery process is to
connect different stages into the complete chain process. All efforts in designing
multiproduct scenarios are looking to increase the economic feasibility of global
production of biofuels, but, as can be seen, a biorefinery configuration involves
many decisions to be made, including alternatives for cultivation, water consumption and nutrients supply, culture condition to trigger accumulation target
products, and a complicated downstream processing to maximize the product
recovery-exploitation. Therefore, in order to define the adequate processing pathway of the microalgae biomass, different scenarios have to be analyzed using
optimization techniques, including techno-economic aspects and sustainability
issues.
5 Economic and Sustainability Aspects
Detailed information and fundamentals about economic aspects and life cycle
assessment (LCA) of microalgae biofuels will be presented in Chaps. 6 and 7 of
this book, and this section is specific for the biorefinery strategy.
Most of the current research about microalgae biofuels is based on the potential
of biodiesel from microalgae lipids (Chisti 2007); this optimistic study was performed in an extraordinary situation with extremely high oil prices, favoring the
biofuel development. At that time, the initial challenge to decrease its production
cost to 0.48 USD/L was established. Afterward, Wijffels et al. (2010) established
that this biodiesel price was achievable, when considering a microalgae biorefinery,
based on the valorization of different biochemical fractions and high-value-added
products. Up to date, several studies have been published on the economic analysis
of microalgae-based processes (Acién et al. 2017; Davis et al. 2016; Douskova et al.
2009; Hoffman et al. 2017; Norsker et al. 2011; Slade and Bauen 2013; Tredici
et al. 2015). Recently, reviews about techno-economic evaluations of microalgae
biofuels, from a biorefinery point of view, were performed by analyzing a great
variety of scenarios (de Boer and Bahri 2015; Laurens et al. 2017b). Those works
report prices ranging from 0.88 USD/L up to 24.60 USD/L, concluding, on the
5 Microalgae Biorefineries for Energy …
125
processing the whole biomass/the pre-extracted product to final products, (6) process integration of streams and recycling of materials, reducing wastes, and finally
(7) a life cycle analysis. In the case of high-value products, Eppink et al. (2017)
suggested specific recommendations about harvesting, cell disruption, and extraction methods. They indicated the need to know the composition and strength of the
cell wall, and localization of the target compound in the cytoplasm, as well as to
select moderated harvesting methods and mild cell disruption, removing first the
cell wall and after, the organelle disruption. The next step is the selective separation
of hydrophobic (lipids, pigments) and hydrophilic (proteins, carbohydrates) fractions while keeping full functionality and finally, fractioning the hydrophilic and
hydrophobic component mixtures to recover target compounds for different market
applications. The final step for the implementation of a biorefinery process is to
connect different stages into the complete chain process. All efforts in designing
multiproduct scenarios are looking to increase the economic feasibility of global
production of biofuels, but, as can be seen, a biorefinery configuration involves
many decisions to be made, including alternatives for cultivation, water consumption and nutrients supply, culture condition to trigger accumulation target
products, and a complicated downstream processing to maximize the product
recovery-exploitation. Therefore, in order to define the adequate processing pathway of the microalgae biomass, different scenarios have to be analyzed using
optimization techniques, including techno-economic aspects and sustainability
issues.
5 Economic and Sustainability Aspects
Detailed information and fundamentals about economic aspects and life cycle
assessment (LCA) of microalgae biofuels will be presented in Chaps. 6 and 7 of
this book, and this section is specific for the biorefinery strategy.
Most of the current research about microalgae biofuels is based on the potential
of biodiesel from microalgae lipids (Chisti 2007); this optimistic study was performed in an extraordinary situation with extremely high oil prices, favoring the
biofuel development. At that time, the initial challenge to decrease its production
cost to 0.48 USD/L was established. Afterward, Wijffels et al. (2010) established
that this biodiesel price was achievable, when considering a microalgae biorefinery,
based on the valorization of different biochemical fractions and high-value-added
products. Up to date, several studies have been published on the economic analysis
of microalgae-based processes (Acién et al. 2017; Davis et al. 2016; Douskova et al.
2009; Hoffman et al. 2017; Norsker et al. 2011; Slade and Bauen 2013; Tredici
et al. 2015). Recently, reviews about techno-economic evaluations of microalgae
biofuels, from a biorefinery point of view, were performed by analyzing a great
variety of scenarios (de Boer and Bahri 2015; Laurens et al. 2017b). Those works
report prices ranging from 0.88 USD/L up to 24.60 USD/L, concluding, on the
5 Microalgae Biorefineries for Energy …
125