Page 153 - Lignocellulosic Biomass to Liquid Biofuels

128 Lignocellulosic Biomass to Liquid Biofuels

life cycle, while organic products could be decomposed through a biolog-
ical cycle. Moreover, all primary raw materials and the energy needed
should be derived from renewable sources and efficiently use to improve
potential savings.
A very deep change is obviously needed in the structure of industrial
systems to extend this logic across the economy. In this view the biorefin-
ery approach embodies the circular economy concept. Biorefinery is the
sustainable processing of biomass into a wide spectrum of
marketable bioproducts, such as food, feed, biomaterials, and chemicals,
and bioenergy, such as fuels, power, and/or heat [3]. The development of
a sustainable concept of biorefinery needs to solve the problem related to
the competition with food chain, the impact on water use, the use of land
to biomass supply, the influence on the balance of soil carbon stock and
on its fertility, the balance of gas emissions, the impact on biodiversity,
the potential toxicological risks, and the energy efficiency. Moreover, the
concept of biorefinery should take into account the impacts on interna-
tional and regional dynamics. For this reason the sustainability assessment
is not an absolute number but should be compared to conventional sys-
tems that provide the same products and services [4].
However, new biorefinery concepts are still mostly in the R&D
(Research and Development) phase or in pilot or small-scale demonstra-
tion state, and their industrial application is still far away, but these new
concepts will be implemented in different countries in the medium term
(2015 25) [5], although current economic conditions could be a reason
for a delay in the application of these concepts.
The technologies to implement these processes still need to become
commercial, but they require an important effort due to the complexity
in terms of feedstocks used (e.g., algae, energy crops, and wood chips
from short rotation), as well as the spectrum of bioproducts. Among these,
particular attention is paid to microbial cultures that can be established to
convert lignocellulosic sugars or low-value hydrophobic substrates into
biodiesel and biochemicals.

4.2 Potentiality of lignocellulosic biomass as a source of
biodiesel
Biomass and biomass-derived materials have been considered one of the
most promising alternatives to fossil resources to fuel production, since
they are a sustainable source of organic carbon with net zero carbon