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Keywords Microalgae/cyanobacteria · Photosynthesis · Biological carbon capture
and utilization · Photobioreactor · Microalgae-based processes · Microalgae-based
products · Biosynthesis · Volatilomics · Commercial application · Recovery ·
Environment
2.1 Introduction
Carbon dioxide (CO 2 ) is a chemical molecule that constitutes the carbon cycle of the
terrestrial atmosphere. As an outcome of the anthropogenic action, the natural emissions and CO 2 absorptions have been adversely affected. Without a doubt, we can
point to the massive use of fossil fuels as the primary source of greenhouse gases
(GHGs), of which CO 2 is the most significant contributor to global climate change
(Chaudry 2019). According to the International Energy Agency, in 2016, CO 2 emissions were 32.31 Gt CO2 , in 2017 emissions increased by around 1.5%, and the forecast for the coming years is that the levels increase more and more (IEA 2017).
These data encourage scientists, researchers, government agencies, and public
and private companies around the world to seek the development and improvement
of technologies for carbon capture and storage or utilization. However, both techniques face technical and economic limitations, in addition to the low knowledge
and public acceptance, which makes industrial rollout unsuccessful (Arning et al.
2019).
Among the various options, biological carbon capture has gained substantial
attention because it offers a double solution: the conversion into multiple complex
value-added molecules of commercial interest associated with improved environmental performance (Choi et al. 2019). Thus, autotrophic organisms and some
microorganisms such as bacteria, cyanobacteria, and microalgae can reduce CO 2 to
produce organic compounds from key enzymes, such as carbonic anhydrase and
ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) during the photosynthesis, and this is considered as the biological mechanism of nature quantitatively
more efficient in the CO 2 bioconversion (Hicks et al. 2017).
Microalgae, for example, are recognized as the atmospheric carbon sink, and, for
this reason, they have been the target of many works in the field of biotechnology.
These microorganisms have relatively simple growth requirements (nutrients, CO 2 ,
luminosity, pH, and temperature) and high photosynthetic rates, which induce a better CO 2 conversion. Regarding cultivation, microalgae can grow both in open or
closed systems, and the latter (photobioreactors) is the most acceptable because of
better control of the operating conditions (Vo et al. 2019).
At the same time, CO 2 is removed from the emissions when submitted to
microalgae- based processes; this molecule can be simultaneously biotransformed
into biomass, which can be applied for food production, animal feed, biofertilizer,
biofuels, bioenergy, and other products of photosynthetic metabolism. These, in
turn, are represented by the production of oxygen, exopolymers, carbonate, bicarI. A. Severo et al.
Keywords Microalgae/cyanobacteria · Photosynthesis · Biological carbon capture
and utilization · Photobioreactor · Microalgae-based processes · Microalgae-based
products · Biosynthesis · Volatilomics · Commercial application · Recovery ·
Environment
2.1 Introduction
Carbon dioxide (CO 2 ) is a chemical molecule that constitutes the carbon cycle of the
terrestrial atmosphere. As an outcome of the anthropogenic action, the natural emissions and CO 2 absorptions have been adversely affected. Without a doubt, we can
point to the massive use of fossil fuels as the primary source of greenhouse gases
(GHGs), of which CO 2 is the most significant contributor to global climate change
(Chaudry 2019). According to the International Energy Agency, in 2016, CO 2 emissions were 32.31 Gt CO2 , in 2017 emissions increased by around 1.5%, and the forecast for the coming years is that the levels increase more and more (IEA 2017).
These data encourage scientists, researchers, government agencies, and public
and private companies around the world to seek the development and improvement
of technologies for carbon capture and storage or utilization. However, both techniques face technical and economic limitations, in addition to the low knowledge
and public acceptance, which makes industrial rollout unsuccessful (Arning et al.
2019).
Among the various options, biological carbon capture has gained substantial
attention because it offers a double solution: the conversion into multiple complex
value-added molecules of commercial interest associated with improved environmental performance (Choi et al. 2019). Thus, autotrophic organisms and some
microorganisms such as bacteria, cyanobacteria, and microalgae can reduce CO 2 to
produce organic compounds from key enzymes, such as carbonic anhydrase and
ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) during the photosynthesis, and this is considered as the biological mechanism of nature quantitatively
more efficient in the CO 2 bioconversion (Hicks et al. 2017).
Microalgae, for example, are recognized as the atmospheric carbon sink, and, for
this reason, they have been the target of many works in the field of biotechnology.
These microorganisms have relatively simple growth requirements (nutrients, CO 2 ,
luminosity, pH, and temperature) and high photosynthetic rates, which induce a better CO 2 conversion. Regarding cultivation, microalgae can grow both in open or
closed systems, and the latter (photobioreactors) is the most acceptable because of
better control of the operating conditions (Vo et al. 2019).
At the same time, CO 2 is removed from the emissions when submitted to
microalgae- based processes; this molecule can be simultaneously biotransformed
into biomass, which can be applied for food production, animal feed, biofertilizer,
biofuels, bioenergy, and other products of photosynthetic metabolism. These, in
turn, are represented by the production of oxygen, exopolymers, carbonate, bicarI. A. Severo et al.