Page 70 - Advances in Eco-Fuels for a Sustainable Environment

Ecofuel feedstocks and their prospects 47

and could enhance the potential of metabolic engineering to influence biofuel
production.
The use of microalgae as a potential feedstock may accelerate traditional applica-
tions. Energy conversion methods such as direct combustion and fermentation should
be prioritized due to environmental feasibility and economic possibility for both
domestic and industrial use.
Notwithstanding the progress made so far and future perspectives, at the moment
microalgae, cyanobacteria, and other photosynthetic organisms, native or engineered,
do not seem to have a near-term potential for generating readily marketable biofuels,
due to persisting technological and economic constraints, but have initiated innovative
biorefinery options for microalgae industry development.
Biofuels from algae are technically feasible due to their sustainability, and this puts
them in the best position to potentially displace fuels obtained from crude oil. The
future of algae biofuel is based on developing cost-effective approaches for the most
efficient technologies that will make the commercialization of this biofuel quicker and
successful [52]. A significant portion of the total hydrocarbon fuel consumed by the
world today can be potentially replaced by algae biofuels with minimum or no envi-
ronmental footprint.
The utilization of microalgal biomass as the basis for future biorefineries is both a
logical and promising concept for a gradual transition to a bio-based economy.
Despite the presence of process bottlenecks in biofuel synthesis, there has been a huge
increase in interest in this type of technology. Integrated sugarcane-microalgae bio-
refineries can represent a first approach to microalgae utilization in biofuels produc-
tion, where the algal utilization of CO 2 produced during ethanol fermentation and
obtained from AD of vinasse can be practical and an advantage in terms of integration,
instead of utilizing flue gas emissions. Scientific data concerning growth of different
microalgae species, wild and genetically modified ones, as well as innovative config-
urations and novel bioreactor designs for optimization of CO 2 uptake and microalgae
concentration and productivity are major improvements to focus on [65].
High-value coproducts derived from modified process chains could enhance the
overall economics of biofuel production through system integration and bioengineer-
ing applied to integrated biorefineries. Persistent R&D activities, innovative market-
ing strategies, and successful integration of technologies may help contribute to the
consolidation and sustainability of biofuel prospects.

2.8 Conclusions

The EU, United States, and many other countries have irrevocably embraced a course
of action that should lead to the substitution of a consistent and (in time) increasing
percentage of fossil fuels with renewable energy. The foreseen schedules of this par-
adigmatic change in energy policy may be overoptimistic (few countries have so far
achieved the turnover levels that were initially foreseen), but the momentum in this
field is fully geared toward the firm pursuit of targets. The main current obstacle
in further development of ecofuels is, curiously enough, daily economics: the fossil