2 Microalgae as Biofuel Feedstock
The introduction of commercially viable microalgal feedstock for biofuels production is among the most important bottlenecks of the whole process and therefore, numerous published patents exist in this regards. Algal biomass could undergo
any of the following main pathways to be converted into biofuels: (1) extraction and
transesterification of triglycerides to produce biodiesel; (2) fermentation of carbohydrates to produce bioalcohols (e.g., bioethanol and biobutanol); (3) anaerobic
digestion to produce biogas (biomethane); and (4) gasification or other thermochemical conversions of the biomass (Craggs et al. 2011). The details of processes
and systems to convert algal biomass for production of biofuels are the subject of
the patents such as US7977076B2, US2012/0329099, US2012/0288917, US2012/
0283496, WO2009158028A2, CN102120938A, US8308949, US8211308. In all
these inventions, it has been stressed that microalgae cultivation in an aquatic
environment could harness sunlight energy in the form of carbohydrates by photosynthesis. This is environmentally important as the combustion of
petroleum-derived energy carriers interferes with the carbon pool, i.e., the energy of
sunlight stored in the past, leading to an increased level of atmospheric carbon
while algal biofuels capture these released carbon atoms on a current basis.
A patent analysis by using a major generic keyword, i.e., “microalgae biodiesel”
in the title, abstract or full text, led to 49 hits in the Worldwide EN database (https://
www.epo.org). The related patents were also mined in the USPTO Patent Full-Text
and Image Database (http://www.uspto.gov/) from 1976 to 2017, and 107 hits were
found. While using the free trial version of Matheo Patent software, the number of
patents found using the same keyword was only one since the year 2011. However,
by using “microalgae” as keyword, more than 2048 US patents describing
microalgae potential applications were found since the year 1979. These patents are
mostly focused on limited applications such as introduction of novel cultivation
conditions (e.g., SU678065, SU663723, and SU686686), or for water treatment
(e.g., SU701570). After a lag phase between 1960s and 1990s, the publication of
patents related to the general term “microalgae” experienced a slight increase.
Interestingly, the introduction of the industrial applications of microalgal biotechnology led to an exponential growth in the number of patents following the
year 2007.
Apart from the liquid biofuels produced from microalgae such as bioethanol and
biodiesel, production of other bioenergy carriers such as biohydrogen and biomethane from this feedstock is also of substantial interest. Researchers have also
developed genetically modified algae to produce specific biofuel precursors. In the
subsequent sections, some examples of algal potentials in bioenergy production are
presented. Contrary to the algae-related applications published in last decades
(usually disclosing methods that were interesting, but not necessarily commercial),
in the past 6 years, both aspects of novelty and commercial viability have been
considered while some patents have also taken environmental considerations
(e.g., life cycle assessments) into account.
14 Recent Patents on Biofuels from Microalgae
293
The introduction of commercially viable microalgal feedstock for biofuels production is among the most important bottlenecks of the whole process and therefore, numerous published patents exist in this regards. Algal biomass could undergo
any of the following main pathways to be converted into biofuels: (1) extraction and
transesterification of triglycerides to produce biodiesel; (2) fermentation of carbohydrates to produce bioalcohols (e.g., bioethanol and biobutanol); (3) anaerobic
digestion to produce biogas (biomethane); and (4) gasification or other thermochemical conversions of the biomass (Craggs et al. 2011). The details of processes
and systems to convert algal biomass for production of biofuels are the subject of
the patents such as US7977076B2, US2012/0329099, US2012/0288917, US2012/
0283496, WO2009158028A2, CN102120938A, US8308949, US8211308. In all
these inventions, it has been stressed that microalgae cultivation in an aquatic
environment could harness sunlight energy in the form of carbohydrates by photosynthesis. This is environmentally important as the combustion of
petroleum-derived energy carriers interferes with the carbon pool, i.e., the energy of
sunlight stored in the past, leading to an increased level of atmospheric carbon
while algal biofuels capture these released carbon atoms on a current basis.
A patent analysis by using a major generic keyword, i.e., “microalgae biodiesel”
in the title, abstract or full text, led to 49 hits in the Worldwide EN database (https://
www.epo.org). The related patents were also mined in the USPTO Patent Full-Text
and Image Database (http://www.uspto.gov/) from 1976 to 2017, and 107 hits were
found. While using the free trial version of Matheo Patent software, the number of
patents found using the same keyword was only one since the year 2011. However,
by using “microalgae” as keyword, more than 2048 US patents describing
microalgae potential applications were found since the year 1979. These patents are
mostly focused on limited applications such as introduction of novel cultivation
conditions (e.g., SU678065, SU663723, and SU686686), or for water treatment
(e.g., SU701570). After a lag phase between 1960s and 1990s, the publication of
patents related to the general term “microalgae” experienced a slight increase.
Interestingly, the introduction of the industrial applications of microalgal biotechnology led to an exponential growth in the number of patents following the
year 2007.
Apart from the liquid biofuels produced from microalgae such as bioethanol and
biodiesel, production of other bioenergy carriers such as biohydrogen and biomethane from this feedstock is also of substantial interest. Researchers have also
developed genetically modified algae to produce specific biofuel precursors. In the
subsequent sections, some examples of algal potentials in bioenergy production are
presented. Contrary to the algae-related applications published in last decades
(usually disclosing methods that were interesting, but not necessarily commercial),
in the past 6 years, both aspects of novelty and commercial viability have been
considered while some patents have also taken environmental considerations
(e.g., life cycle assessments) into account.
14 Recent Patents on Biofuels from Microalgae
293