oxygen facilitating the reaction in the cathode of the chamber. Bioelectricity is
produced by bacteria in the anode, which oxidize organic matter and produce
electrons. Those electrons are transferred to the cathode electrode with an external
circuit and produce electricity. The bacteria can be used for biodegradable waste
treatment, and with the help of microalgae, the organic and inorganic load of the
water can be reduced.
From all the above-mentioned bioproducts, the role of microalgae in the human
diet is well established, but other applications are currently under development:
biofuel production of pharmaceutical compounds, bioremediation, cosmetic active
ingredients. Furthermore, microalgae produce many environmental benefits, such as
carbon fixation, oxygen release, heavy metal removal, and wastewater treatment
that provide energy savings and supply oxygen to anaerobic bacteria (Uggetti and
Puigagut 2016). However, market is clearly dependent on actual investigation of
new technologies, and mainly on governmental policies such as subsidies and
mandated use of biofuels (Gorry et al. 2017).
3 Microalgal Biomass Processing
In order to maximize the potential of microalgae biomass, the whole chain process
development should be defined in an integrated way, starting from an adequate
supply of nutrients and CO 2 , good harvesting methods, dewatering, and downstream processing (Mata et al. 2010; Toledo-Cervantes and Morales 2014). For this,
it is necessary to know not only the potential added value that can be obtained, the
microalgae cell wall strength and the composition and localization of cellular
components in order to break down the cell wall properly to avoid product loss
(Gerardo et al. 2015; Pei et al. 2010; Roux et al. 2017), but also the available
processing technologies and the sequence of separation; these latter ones are needed
to maintain the integrity of the possible products maximizing the recovery and to
produce biofuels. Each biorefinery stage for processing microalgal biomass would
be linked to the characteristics of each specific strain and biochemical composition,
and the route to obtain bioenergy must be defined too. Main downstream processing
technologies are explained in the following sections (see Fig. 1), and the routes to
obtain diverse biofuels are shown as well.
3.1 Downstream Processing
3.1.1 Harvesting Technologies
Harvesting accounts for 20–30% of microalgae biomass production cost that is
associated with the recovery of microalgae biomass from diluted streams (Barros
et al. 2015; Pei et al. 2010; Tan et al. 2014). Harvesting is an energy-intensive
98
P.-L. Gorry et al.
produced by bacteria in the anode, which oxidize organic matter and produce
electrons. Those electrons are transferred to the cathode electrode with an external
circuit and produce electricity. The bacteria can be used for biodegradable waste
treatment, and with the help of microalgae, the organic and inorganic load of the
water can be reduced.
From all the above-mentioned bioproducts, the role of microalgae in the human
diet is well established, but other applications are currently under development:
biofuel production of pharmaceutical compounds, bioremediation, cosmetic active
ingredients. Furthermore, microalgae produce many environmental benefits, such as
carbon fixation, oxygen release, heavy metal removal, and wastewater treatment
that provide energy savings and supply oxygen to anaerobic bacteria (Uggetti and
Puigagut 2016). However, market is clearly dependent on actual investigation of
new technologies, and mainly on governmental policies such as subsidies and
mandated use of biofuels (Gorry et al. 2017).
3 Microalgal Biomass Processing
In order to maximize the potential of microalgae biomass, the whole chain process
development should be defined in an integrated way, starting from an adequate
supply of nutrients and CO 2 , good harvesting methods, dewatering, and downstream processing (Mata et al. 2010; Toledo-Cervantes and Morales 2014). For this,
it is necessary to know not only the potential added value that can be obtained, the
microalgae cell wall strength and the composition and localization of cellular
components in order to break down the cell wall properly to avoid product loss
(Gerardo et al. 2015; Pei et al. 2010; Roux et al. 2017), but also the available
processing technologies and the sequence of separation; these latter ones are needed
to maintain the integrity of the possible products maximizing the recovery and to
produce biofuels. Each biorefinery stage for processing microalgal biomass would
be linked to the characteristics of each specific strain and biochemical composition,
and the route to obtain bioenergy must be defined too. Main downstream processing
technologies are explained in the following sections (see Fig. 1), and the routes to
obtain diverse biofuels are shown as well.
3.1 Downstream Processing
3.1.1 Harvesting Technologies
Harvesting accounts for 20–30% of microalgae biomass production cost that is
associated with the recovery of microalgae biomass from diluted streams (Barros
et al. 2015; Pei et al. 2010; Tan et al. 2014). Harvesting is an energy-intensive
98
P.-L. Gorry et al.