96
R. Abdulla et al.
Furthermore, the yeast concentration in the fermentation medium decreased after
24 h as reported by Harun and Danquah (2011b). Lower yeast concentration resulted
in the decrease of bioethanol production.
Other than previous studies on microalgae, the time course of the ethanol fermentation was also studied on other biomass. Yu et al. (2014) reported that ethanol was
accumulated rapidly during the first 24 h of fermentation when they were working
with fermented sweet sorghum bagasse. This indicates that maximum bioethanol
production reached by 24 h with ethanol yield of 157.68 g/kg. However, a study on
oil palm fond showed different optimum time for alcoholic fermentation. Hong et al.
(2013) reported that the optimum time for maximum bioethanol was at 36 h instead
of 24 h. From here, it is believed that optimum fermentation time for bioethanol
production may be biomass-specific or may be influenced by the biomass sources.
6 Economical Aspects of Bioethanol Production
from Microalgae
It is forecasted that microalgal biomass can contribute to the sustainable feedstock
sources for bioethanol in the incoming years. The valuable characteristics which
come from its high productivity rate, adaptability to the extreme conditions and different water environment and its form of renewable energy are the major driven
forces that make it the fuels of the future (Brownbridge et al. 2013). Though these
are the main advantages, problems still arise, especially on its viability for the largescale production. Technical challenges, including high input cost for cultivation and
harvesting, inadequate consistency in conversion technologies as well as high energy
requirements are some constraints that need to be addressed for a better microalgalbased bioethanol commercialization (Brownbridge et al. 2014). Each stage in the
cycle during the production process must be taken into account during the economical analysis. The high cost of supply chains such as raw materials, storage,
transportation and processing technologies mainly affects the economic viability of
bioethanol at this stage. Figure 1.9 shows the general production flow of bioethanol
from microalgae feedstock which involves strain selection, cultivation, harvesting,
conversion technologies and finally production of bioethanol.
There are many conflicts that need to be managed properly in the first place
before any difficulties occur during the process of bioethanol production. According
to IAE Bioenergy (2011), to compete with the fuels derived from non-renewable
energy sources, several technical challenges must be confronted. These include the
identification of production chains with net energy output, targeted research and
development (R&D) which focus on reducing the cost in all segments of the production spectrum, the intense identification of algal strain high production rates and
the initiatives to integrate microalgal biofuels into the existing transportation sector.
For the past several years, the majority of the researchers conducted are focusing on
the sustainability and the economic viability of microalgal biofuels. As an example,
R. Abdulla et al.
Furthermore, the yeast concentration in the fermentation medium decreased after
24 h as reported by Harun and Danquah (2011b). Lower yeast concentration resulted
in the decrease of bioethanol production.
Other than previous studies on microalgae, the time course of the ethanol fermentation was also studied on other biomass. Yu et al. (2014) reported that ethanol was
accumulated rapidly during the first 24 h of fermentation when they were working
with fermented sweet sorghum bagasse. This indicates that maximum bioethanol
production reached by 24 h with ethanol yield of 157.68 g/kg. However, a study on
oil palm fond showed different optimum time for alcoholic fermentation. Hong et al.
(2013) reported that the optimum time for maximum bioethanol was at 36 h instead
of 24 h. From here, it is believed that optimum fermentation time for bioethanol
production may be biomass-specific or may be influenced by the biomass sources.
6 Economical Aspects of Bioethanol Production
from Microalgae
It is forecasted that microalgal biomass can contribute to the sustainable feedstock
sources for bioethanol in the incoming years. The valuable characteristics which
come from its high productivity rate, adaptability to the extreme conditions and different water environment and its form of renewable energy are the major driven
forces that make it the fuels of the future (Brownbridge et al. 2013). Though these
are the main advantages, problems still arise, especially on its viability for the largescale production. Technical challenges, including high input cost for cultivation and
harvesting, inadequate consistency in conversion technologies as well as high energy
requirements are some constraints that need to be addressed for a better microalgalbased bioethanol commercialization (Brownbridge et al. 2014). Each stage in the
cycle during the production process must be taken into account during the economical analysis. The high cost of supply chains such as raw materials, storage,
transportation and processing technologies mainly affects the economic viability of
bioethanol at this stage. Figure 1.9 shows the general production flow of bioethanol
from microalgae feedstock which involves strain selection, cultivation, harvesting,
conversion technologies and finally production of bioethanol.
There are many conflicts that need to be managed properly in the first place
before any difficulties occur during the process of bioethanol production. According
to IAE Bioenergy (2011), to compete with the fuels derived from non-renewable
energy sources, several technical challenges must be confronted. These include the
identification of production chains with net energy output, targeted research and
development (R&D) which focus on reducing the cost in all segments of the production spectrum, the intense identification of algal strain high production rates and
the initiatives to integrate microalgal biofuels into the existing transportation sector.
For the past several years, the majority of the researchers conducted are focusing on
the sustainability and the economic viability of microalgal biofuels. As an example,