hydrogenase-catalyzed reduction of protons by the electrons generated from photosynthetic oxidation of water. Sunlight acts as generator to supply the required
energy to continue this stepwise reaction (Lee 2010). In spite of the numerous
research efforts put into improving algal H 2 production, the limited rate of this
reaction has so far made H 2 production commercially impractical.
2.4 Biogas (Biomethane)
Following lipid (oil) extraction or ethanol fermentation, the remaining algal biomass could also be anaerobically digested to produce biogas. If upgraded, i.e., by
increasing the methane content of the gas stream, biogas can be used directly for
heating or for electricity generation. Conversion of wet algal biomass to biomethane
along with a liquid fertilizer (anaerobic digestate) is an advisable strategy to harness
the majority of the remained energy and nitrogen contained in the algal biomass
after oil and/or carbohydrates extraction (Scott et al. 2010). Biogas obtained from
microalgae was found 7–13% more enriched in terms of its methane content in
comparison with the biogas obtained from maize (Sialve et al. 2009), but the
production was still limited by the relatively high N content of biomass or in
another word, the ammonia inhibition effect. An average yield of approximately
0.30 m
3 (0.20 kg) CH 4 /kg algal biomass (energy value equivalent to 1 L of petrol
(34 MJ) for each cubic meter of biogas) was reported by Craggs et al. (2011).
2.5 Biomass to Liquid (BTL) Fuel
Biomass to liquid (BTL) is an integrated process aimed at fuel by thermal conversion of biomass. More specifically, the biomass gasified through biosyngas
production systems is converted into liquid fuels through different processes such as
Fischer–Tropsch (Medina et al. 2010). Carbon monoxide and hydrogen can be
produced from gasification of any biomass such as algal feedstock. Methanol for
instance can then be produced through direct reaction between these gases. US
Patents 20090321349, 8163041B1 as well as WO2012109720A1 and
WO2014057102A1 present further details on the catalysts and methods involved in
the conversion of syngas to liquid fuels.
3 Microalgal Biofuels-Related Patents
Based on a logical order, the microalgal biofuels-related patents could be categorized into three major groups, i.e., patents concerning upstream, mainstream, and
downstream strategies. The patents presented were selected from the Matheo patent
database software which contains more than 80 million patents.
14 Recent Patents on Biofuels from Microalgae
295
energy to continue this stepwise reaction (Lee 2010). In spite of the numerous
research efforts put into improving algal H 2 production, the limited rate of this
reaction has so far made H 2 production commercially impractical.
2.4 Biogas (Biomethane)
Following lipid (oil) extraction or ethanol fermentation, the remaining algal biomass could also be anaerobically digested to produce biogas. If upgraded, i.e., by
increasing the methane content of the gas stream, biogas can be used directly for
heating or for electricity generation. Conversion of wet algal biomass to biomethane
along with a liquid fertilizer (anaerobic digestate) is an advisable strategy to harness
the majority of the remained energy and nitrogen contained in the algal biomass
after oil and/or carbohydrates extraction (Scott et al. 2010). Biogas obtained from
microalgae was found 7–13% more enriched in terms of its methane content in
comparison with the biogas obtained from maize (Sialve et al. 2009), but the
production was still limited by the relatively high N content of biomass or in
another word, the ammonia inhibition effect. An average yield of approximately
0.30 m
3 (0.20 kg) CH 4 /kg algal biomass (energy value equivalent to 1 L of petrol
(34 MJ) for each cubic meter of biogas) was reported by Craggs et al. (2011).
2.5 Biomass to Liquid (BTL) Fuel
Biomass to liquid (BTL) is an integrated process aimed at fuel by thermal conversion of biomass. More specifically, the biomass gasified through biosyngas
production systems is converted into liquid fuels through different processes such as
Fischer–Tropsch (Medina et al. 2010). Carbon monoxide and hydrogen can be
produced from gasification of any biomass such as algal feedstock. Methanol for
instance can then be produced through direct reaction between these gases. US
Patents 20090321349, 8163041B1 as well as WO2012109720A1 and
WO2014057102A1 present further details on the catalysts and methods involved in
the conversion of syngas to liquid fuels.
3 Microalgal Biofuels-Related Patents
Based on a logical order, the microalgal biofuels-related patents could be categorized into three major groups, i.e., patents concerning upstream, mainstream, and
downstream strategies. The patents presented were selected from the Matheo patent
database software which contains more than 80 million patents.
14 Recent Patents on Biofuels from Microalgae
295