Page 256 - Lignocellulosic Biomass to Liquid Biofuels

212 Lignocellulosic Biomass to Liquid Biofuels

CO water mass transfer through the addition of nanoparticles.
Recently, methyl-functionalized silica and methyl-functionalized cobalt
ferrite silica (CoFe 2 O 4 @SiO 2 CH 3 ) types of nanoparticles are used to
increase the syngas water mass-transfer rate successfully. Each type of
nanoparticle is efficient for syngas fermentation, and effective production
of ethanol and acetic acid that enhanced during syngas fermentation
using C. ljungdahlii [55].

6.8 Integrated biorefinery

A biorefinery is the integration of the conversion process, which is associ-
ated with equipment or specific reactor for the production of various types
of biofuels, chemicals, and other bio-based products from lignocellulosic
feedstocks [56 58]. Biorefineries apply the biomass-based feedstocks with-
out producing environmental pollutant and toxic wastes. Among these,
bioethanol is the most valuable product from biorefinery and used as the
transportation fuels with the mixture of gasoline with various ratios. The
energy content of ethanol is about 2/3 in comparison to gasoline. As a
result, ethanol mixed with gasoline up to 10% is usually used in the gaso-
line engines, where there is no modification needed to the existing design
[59]. Syngas fermentation also produces some by-products (acetic and
butyric acids, and butanol) which are also valuable [60].For theenhancing
of yield of bioethanol/biobutanol, various types of nanoparticles are used
for syngas fermentation. It is happening due to the significantly higher sur-
face area-to-mass ratio of amine group, which absorbs acetic acid from the
fermentation medium. As a result, absorbed acid recovered readily as a by-
product [32,60]. The nanomaterials can be the ability to regenerate by
controlling the pH level of the fermentation broth. The lignin-based bio-
mass is always considered as the low-value feedstocks, which are difficult
to convert entirely in biochemical-based ethanol production plant.
Therefore, the integrated biorefinery concept to be applicable for the
mostly available lignocellulosic biomasses to have maximum yield of the
product and to make the process more efficient [61].

6.9 Conclusion
The fermentation of biomass-based syngas is a promising technology for
the production of bioethanol. This process offers significant advantages as
it allows the conversion of whole biomass, including lignin and it avoids