Cellulosic ethanol production

L-ldh gene was inactivated, was reported to produce increased acetic acid (16.4-16.8 mM) and ethanol (38.6-40.8 mM) with neglectable amounts of lactic acid (Desai et al., 2004). Additional manipulations of this microbe are needed to achieve efficient simultaneous thermophilic saccarification and fermentation for cellulosic ethanol production. 

Cellulosic ethanol production is based on agricultural waste, such as wheat stalks, that has been treated with enzymes to break the waste down into component sugars. 

In cellulosic ethanol production processes, a pretreatment procedure is needed to disrupt the recalcitrant structure of the lignocellulosic materials so that the cellulose can be more efficiently hydrolyzed by cellulase enzymes [2], These pretreatments include physical, biological, and chemical ways, such as uncatalyzed steam explosion, liquid hot water, dilute acid, flow-through acid pretreatment, lime, ammonium fiber/freeze explosion, and ammonium recycle percolation [3, 4], Most of these methods involve a high temperature requirement, which is usually achieved through convection- or conduction-based heating. 

Repeatability of Corn Stover Traits Related to Cellulosic Ethanol Production... 

Materials destined for cellulosic ethanol production have been evaluated, and they were found to contain low relative concentrations of fatty acids. Relative to the amount of ethanol produced, the amount of fatty acid byproduct is actually quite significant. Assuming a t q)ical yield of 20% ethanol and 2% fatty acid means that a minimum of 10% of an ethanol producer s high value products could be in the form of fatty acids (59). It has been claimed that microalgal biodiesel is a better alternative than bioethanol from sugarcane (13). 

Dawson L, Boopathy R. (2008). Cellulosic ethanol production from sugarcane bagasse without enzymatic saccharification. BioResources, 3, 452-460. 

An economically feasible process for industrial cellulosic ethanol production requires a high titer ethanol process due to the high energy demands of ethanol distillation [99]. In addition, increasing the final ethanol titer would have a significant effect on lowering capital costs due to the reduced size of the... 

Ryu, S. and Karim, M.N. (2011) A whole cell biocatalyst for cellulosic ethanol production from dilute... 

EPFBF) for cellulosic ethanol production. Applied Biochemistry and Biotechnology 2010,162,1847-1857. 

Yi, Z., Zhongli, R, Zhang, R. Overview of biomass pretreatment for cellulosic ethanol production. International Journal of Agricultural and Biological Engineering 2009,2, 51-68. 

Shuai, L., Yang, Q., Zhu, J.Y., et al., 2010. Comparative study of SPORL and dilute acid pretreatments of softwood spruce for cellulose ethanol production. Bioresource Technology 101,3106-3114. 

Another question regards the cost of the enzymes, which are extremely important for the biochemical production of the sugars that will eventually be fermented, thus producing bioethanol. They are indispensable for breaking down the cellulose, a process better known as enzymatic hydrolysis. However, the price of these enzymes is high. Also at the same time, ceUulase and hemiceUulose, which are used in the production of cellulosic ethanol, are more expensive when compared to their first-generation counterparts. For instance, enzymes required for com ethanol production cost US 2.64—5.28 per cubic meter of ethanol produced, while those needed for cellulosic ethanol production are projected to cost US 79.25 (Sainz, 2011). 

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