Page 228 - Lignocellulosic Biomass to Liquid Biofuels

184 Lignocellulosic Biomass to Liquid Biofuels

Even though there are some massive advantages associated with the
utilization of liquid bio-alcohol as a fuel for the replacement of fossil fuels
or petroleum-based gasoline or diesel, some problems are there while the
productions of biobutanol, say low production yield and high substrate
rate. Hence, many researchers and industrialists have continuously
searched and identified low-cost substrates of renewable lignocellulosic
biomass materials, such as maize stover, agricultural waste, rice straw, bar-
ley straw, and switchgrass, which are the feedstocks, utilized for the pro-
duction of biobutanol [102 105]. At present the production of
biobutanol from lignocellulosic biomass materials is extensively considered
as an alternative feedstock, because the low-cost biomass materials present
in high abundance are broadly distributed in nature [12,13,16]. The first
generation derived biobutanol from food and agricultural resources may
cause some problems, that is, negative impact on food security, increased
food prices, and net energy losses [106]. Globally, the production of bio-
butanol from renewable lignocellulosic biomass carbon feedstocks through
the clostridial ABE fermentation process by solventogenic Clostridium spe-
cies (namely, Clostridium cellulolyticum and Clostridium cellulovorans) since
the ABE fermentation was considered as one of the ancient processes for
large-scale industrial fermentation methods. Generally, the production of
bioethanol from low-cost lignocellulosic biomass is more economical, but
the same feedstocks for the production of higher bio-alcohols, say biobu-
tanol, may cause some challenges due to their recalcitrance to degradation
as well as release of fermentable sugars for further fermentation processes
[12]. In recent years, some researchers have been investigating the produc-
tion of ABE-fermented biobutanol from cellulosic and noncellulosic feed-
stocks. Globally, there are four leading biobutanol producers, namely,
Butamax, Gevo, US Technology Corporation, and Green Biologics, in
large-scale level production for the replacement of fossil fuel crises [107].
Furthermore, the production cost (including the oil price) for biobutanol
from fossil fuel or petrochemical source is B1.35 $/L, whereas the cost of
biobutanol production from bioenergetic crops through ABE fermenta-
tion process is 0.317 $/L, but the production of bioethanol is 0.338 $/L
[108], that is, the utilization of lignocellulosic biomass materials derived
from agricultural crops and residues, forestry plants and residues, plant bio-
mass, etc. may reduce the production cost, renewability, and also promis-
ing materials for the production of biobutanol.