Chapter 12
Biofuels from Microalgae: Biomethane
Fabiana Passos, Cesar Mota, Andrés Donoso-Bravo, Sergi Astals,
David Jeison and Raúl Muñoz
Abstract The high cost of axenic microalgae cultivation in photobioreactors limits
nowadays the potential uses of microalgal biomass as a feedstock for the production
of biodiesel or bioethanol. In this context, microalgae-based wastewater treatment
(WWT) has emerged as the leading method of cultivation for supplying microalgae
at low cost and low environmental impacts, while achieving sewage treatment.
Nonetheless, the year-round dynamics in microalgae population and cell composition when grown in WWTPs restrict the use of this low-quality biomass to biogas
production via anaerobic digestion. Although the macromolecular composition of
the microalgae produced during wastewater treatment is similar to that of sewage
sludge, the recalcitrant nature of microalgae cell walls requires an optimisation of
pretreatment technologies for enhancing microalgae biodegradability. In addition,
the low C/N ratio, the high water content and the suspended nature of microalgae
suggest that microalgal biomass will also benefit from anaerobic co-digestion with
carbon-rich substrates, which constitutes a field for further research. Photosynthetic
microalgae growth can also support an effective CO 2 capture and H 2 S oxidation
from biogas, which would generate a high-quality biomethane complying with most
F. Passos Á C. Mota
Department of Sanitary and Environmental Engineering, Federal University
of Minas Gerais, Campus Pampulha, Antônio Carlos Avenue, 6.627,
Belo Horizonte, MG, Brazil
A. Donoso-Bravo
Inria Chile, Apoquindo Avenue, Floor 12, Las Condes, Santiago 2827, Chile
S. Astals
Advanced Water Management Centre, The University of Queensland,
St. Lucia, QLD 4072, Australia
D. Jeison
Biochemical Engineering School, Pontificia Universidad Católica de Valparaíso,
Avenida Brasil 2085, Valparaíso 2362803, Chile
R. Muñoz (&)
Department of Chemical Engineering and Environmental Technology,
University of Valladolid, Dr. Mergelina, S/N, Valladolid, Spain
e-mail: mutora@iq.uva.es
© Springer International Publishing AG 2018
E. Jacob-Lopes et al. (eds.), Energy from Microalgae, Green Energy
and Technology, https://doi.org/10.1007/978-3-319-69093-3_12
247
Biofuels from Microalgae: Biomethane
Fabiana Passos, Cesar Mota, Andrés Donoso-Bravo, Sergi Astals,
David Jeison and Raúl Muñoz
Abstract The high cost of axenic microalgae cultivation in photobioreactors limits
nowadays the potential uses of microalgal biomass as a feedstock for the production
of biodiesel or bioethanol. In this context, microalgae-based wastewater treatment
(WWT) has emerged as the leading method of cultivation for supplying microalgae
at low cost and low environmental impacts, while achieving sewage treatment.
Nonetheless, the year-round dynamics in microalgae population and cell composition when grown in WWTPs restrict the use of this low-quality biomass to biogas
production via anaerobic digestion. Although the macromolecular composition of
the microalgae produced during wastewater treatment is similar to that of sewage
sludge, the recalcitrant nature of microalgae cell walls requires an optimisation of
pretreatment technologies for enhancing microalgae biodegradability. In addition,
the low C/N ratio, the high water content and the suspended nature of microalgae
suggest that microalgal biomass will also benefit from anaerobic co-digestion with
carbon-rich substrates, which constitutes a field for further research. Photosynthetic
microalgae growth can also support an effective CO 2 capture and H 2 S oxidation
from biogas, which would generate a high-quality biomethane complying with most
F. Passos Á C. Mota
Department of Sanitary and Environmental Engineering, Federal University
of Minas Gerais, Campus Pampulha, Antônio Carlos Avenue, 6.627,
Belo Horizonte, MG, Brazil
A. Donoso-Bravo
Inria Chile, Apoquindo Avenue, Floor 12, Las Condes, Santiago 2827, Chile
S. Astals
Advanced Water Management Centre, The University of Queensland,
St. Lucia, QLD 4072, Australia
D. Jeison
Biochemical Engineering School, Pontificia Universidad Católica de Valparaíso,
Avenida Brasil 2085, Valparaíso 2362803, Chile
R. Muñoz (&)
Department of Chemical Engineering and Environmental Technology,
University of Valladolid, Dr. Mergelina, S/N, Valladolid, Spain
e-mail: mutora@iq.uva.es
© Springer International Publishing AG 2018
E. Jacob-Lopes et al. (eds.), Energy from Microalgae, Green Energy
and Technology, https://doi.org/10.1007/978-3-319-69093-3_12
247