Page 257 - Lignocellulosic Biomass to Liquid Biofuels

Syngas fermentation to bioethanol 213

complex pretreatment stages. In addition, it allows the use of the existing
fermentation technology and is targeted to ethanol well-established mar-
ket. Different studies suggested the use of mesophilic and thermophilic
microorganisms to optimize syngas fermentation in industrial scale. In
addition, the syngas production by gasification and cogasification offers
flexible yield, according to the market demand. Ethanol is the main prod-
uct of this process; other products, such as butanol, 2,3-butanediol, ace-
tate, lactate, butyrate, and other biofuels, can be obtained by changing the
microorganisms used and the operational conditions. In order to develop
a full commercialization of this market, some major limitations have to be
overcome, such as low yield, formation of syngas impurities, reduced mass
transfer from gas to liquid, inefficient microbial consumption, and product
recovery. By overcoming all challenges the fermentation of biomass-based
syngas can become a profitable process to produce ethanol and other valu-
able products that are useful to fulfill the future energy demand.

References
[1] Y. Shen, R.C. Brown, Z. Wen, Syngas fermentation by Clostridium carboxidivorans
P7 in a horizontal rotating packed bed biofilm reactor with enhanced ethanol pro-
duction, Appl. Energy 187 (2017) 585 594.
[2] J.R. Phillips, R.L. Huhnke, H.K. Atiyeh, Syngas fermentation: a microbial conver-
sion process of gaseous substrates to various products, Fermentation 3 (2) (2017) 28.
[3] M. Devarapalli, H.K. Atiyeh, J.R. Phillips, R.S. Lewis, R.L. Huhnke, Ethanol pro-
duction during semi-continuous syngas fermentation in a trickle bed reactor using
Clostridium ragsdalei, Bioresour. Technol. 209 (2016) 56 65.
[4] B. Acharya, P. Roy, A. Dutta, Review of syngas fermentation processes for bioetha-
nol, Biofuels 5 (5) (2014) 551 564.
[5] M.U. Monir, A. Abd Aziz, R.A. Kristanti, A. Yousuf, Syngas production from co-
gasification of forest residue and charcoal in a pilot scale downdraft reactor, Waste
Biomass Valorization (2018).
[6] M.U. Monir, A. Abd Aziz, R.A. Kristanti, A. Yousuf, Gasification of lignocellulosic
biomass to produce syngas in a 50 kW downdraft reactor, Biomass Bioenergy 119
(2018) 335 345.
[7] K. Asimakopoulos, H.N. Gavala, I.V. Skiadas, Reactor systems for syngas fermenta-
tion processes: a review, Chem. Eng. J. 348 (2018) 732 744.
[8] V.S. Sikarwar, M. Zhao, P.S. Fennell, N. Shah, E.J. Anthony, Progress in biofuel
production from gasification, Prog. Energy Combust. Sci. 61 (2017) 189 248.
[9] M.U. Monir, A. Abd Aziz, R.A. Kristanti, A. Yousuf, Co-gasification of empty fruit
bunch in a downdraft reactor: a pilot scale approach, Bioresour. Technol. Rep. 1
(2018) 39 49.
[10] K. Kundu, A. Chatterjee, T. Bhattacharyya, M. Roy, A. Kaur, Thermochemical
conversion of biomass to bioenergy: a review, in: A.P. Singh, R.A. Agarwal, A.K.
Agarwal, A. Dhar, M.K. Shukla (Eds.), Prospects of Alternative Transportation Fuels,
Springer, Singapore, 2018, pp. 235 268.