Fuels and Chemicals from Hemicellulose Sugars - Biotechnology in China: Biofuels and Bioenergy - page 217

lingocellulosics into protein-rich feed and has made possible the improvement of
the nutritional value of cornstalks.
Apart from SCP, the hemicellulose fraction in lignocellulosics has also been
used for furfural and methane gas production [ 146 , 147 ]. The lignocellulosic
substrate such as corncob or rice straw is widely distributed in China. The
hemicellulosic fraction can first be hydrolyzed to pentose-rich sugars using sulfuric
acid as the catalyst. The sugars can be further converted into furfural [ 148 , 149 ].
The residues rich in cellulose can be further converted to ethanol by simultaneous
saccharification and fermentation [ 150 ]. Rice straw is a widely available ligno-
cellulosic resource in China. Pilot scale anaerobic digestion of rice straw to convert
both hemicellulose and cellulose to methane gas has been developed [ 151 , 152 ].
4 Conclusions and Perspectives
The hemicellulose fraction represents as much as 40% of total lignocellulosic
materials. In the development of industrial production of ethanol as a biofuel, it is
crucial to have efficient and cost-effective methods to convert sugars derived from
hemicellulose into either additional ethanol or other valuable byproducts.
At present, the conversion of hemicellulosic substrates to fermentable sugars is
still a key obstacle hindering hemicellulose usage. It is important to develop a
suitable pretreatment method, minimizing the formation of inhibitory compounds
for fermentation organisms, so that the hemicellulose fraction can be utilized for
production of fuels and chemicals by fermentation. In addition, there is still a need
for further development of efficient and cost-effective methods for production of
enzymes for hemicellulose conversion on an industrial scale. Additional chal-
lenges to the process economics of hemicellulose sugars conversion will include
the development of robust efficient microorganisms to ferment hemicellulose
sugars, and also methods for cost-effective recovery of fermentation products.
Acknowledgments Funding for our research was provided by the National Basic Research
Program of China (No. 2011CBA00802), the National Natural Science Foundation of China
(Nos. 20936002; 21006049), the National High Technology Research and Development Program
of China (No. 2011AA02A207), and the Priority Academic Program Development of Jiangsu
Higher Education Institutions.
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