State of the bioethanol production in the USA
 In the USA, bioethanol production has increased dramatically to an annual production of 19 mil kL. However, the substrate used is currently limited to corn and maximum production is predicted to top at 30 mil kL. In the State of the Union speech of January 2006, a plan for early development of bioethanol production technology from "soft-biomass", which is non-food based resources including agricultural wastes (corn stover etc.) and fuel crops (switch grass and poplar), was addressed. Following the previous year's speech, a target was set to produce 130 mil kL of biofuel (ethanol, butanol and biodiesel) by 2017.

Reduction in CO₂ emission by ethanol from soft-biomass
 A report produced by Argonne National Laboratory, published in Science in January 2006, stated that the net energy balance of ethanol produced from soft-biomass becomes positive if switch grass is used as a substrate and 90% reduction in CO₂ emission compared to gasoline can be achieved.

Our R&D into ethanol production technology from soft-biomass
 There are two technological aspects of production technology utilizing soft-biomass; sugar production from soft-biomass and bioconversion of sugars to ethanol. Details on sugar production technology can be found in our "saccharification technology" page. In the bioconversion technology, we utilize a coryneform bacterium, which has been genetically modified to produce ethanol, and the RITE Bioprocess to produce ethanol from soft-biomass. The points below are some of the aspects achieved to establish the ethanol production process.

 (1) High-STY (Space Time Yield: productivity in a unit of reaction volume per hour)
 One of the biggest problems associated with conventional bioprocesses is low STY compared to chemical processes. We have achieved high-STY in the RITE Bioprocess by utilizing growth-arrested microbial cells in the manner of chemical catalysts.

 (2) Simultaneous utilization of C6 and C5 sugars
 Soft-biomass contains C5 sugars as well as C6 sugars whereas starch (from corn) and cane sugar (from sugarcane) contain only C6 sugars. The microorganisms used in conventional processes either do not have the ability to use C5 sugars or preferentially use C6 sugars leading to low yield per substrate. In the RITE Bioprocess, however, C5 and C6 sugars can be utilized simultaneously, leading to greater efficiency.

(3) Reduced susceptibility to fermentation inhibitors
 In conventional ethanol production processes, fermentation inhibitors (phenols and furans) produced during the pre-treatment process in the sugar production stage have been known to inhibit microbial growth. However, as the RITE Bioprocess is independent of microbiol growth, it is not affected by fermentation inhibitors.

Collaborative bioethanol production research with Honda R&D Co.
  We announced RITE-Honda R&D Co. Ltd. collaborative research in September 2006 to achieve early industrialization of the RITE Bioprocess, which possesses technologies essential for ethanol production from soft-biomass as described above. Currently, we are carrying out tests in a pilot plant built in Honda's premises in April 2007 and planning for a test-run of a flexible fuel vehicle supplied with bioethanol produced by our process. As mentioned before, we are attempting to establish this industrialization technology ahead of the rest of the world.

< References >
Engineering of pentose transport in Corynebacterium glutamicum to improve simultaneous utilization of mixed sugars.
Appl. Environ. Microbiol. 85: 105-115. 2009.
M. Sasaki, T. Jojima, H. Kawaguchi, M. Inui and H. Yukawa.

Identification and functional analysis of the gene cluster for L-arabinose utilization in Corynebacterium glutamicum.
Appl. Environ. Microbiol. 75: 3419-3429. 2009.
H. Kawaguchi, M. Sasaki, A.A. Vertès, M. Inui and H. Yukawa.

Simultaneous utilization of D-cellobiose, D-glucose, and D-xylose by recombinant Corynebacterium glutamicum under oxygen-deprived conditions.
Appl. Microbiol. Biotechnol. 81: 691-699. 2008.
M. Sasaki, T. Jojima, M. Inui and H. Yukawa.

Engineering of an L-arabinose metabolic pathway in Corynebacterium glutamicum.
Appl. Microbiol. Biotechnol. 77: 1053-1062. 2008.
H. Kawaguchi, M. Sasaki, A.A. Vertès, M. Inui and H. Yukawa.

Effect of lignocellulose-derived inhibitors on growth of and ethanol production by growth-arrested Corynebacterium glutamicum R.
Appl. Environ. Microbiol. 73: 2349-2353. 2007.
S. Sakai, Y. Tsuchida, H. Nakamoto, S. Okino, O. Ichihashi, H. Kawaguchi, T. Watanabe, M. Inui and H. Yukawa.

Engineering of a xylose metabolic pathway in Corynebacterium glutamicum.
Appl. Environ. Microbiol. 72: 3418-3428. 2006.
H. Kawaguchi, A.A. Vertès, S. Okino, M. Inui and H. Yukawa.

Metabolic engineering of Corynebacterium glutamicum for fuel ethanol production under oxygen-deprivation conditions.
J. Mol. Microbiol. Biotechnol. 8: 243-254. 2004.
M. Inui, H. Kawaguchi, S. Murakami, A.A. Vertès and H. Yukawa.

Bacteria engineered for fuel ethanol production: current status.
Appl. Microbiol. Biotechnol. 63: 258-266. 2003.
B.S. Dien, M.A. Cotta and T.W. Jeffries.