ARS | Publication request: Fuel ethanol production from pretreated agricultural residues by simultaneous saccharification and fermentation

Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 14, 2008
Publication Date: August 17, 2008
Citation: Saha, B.C., Cotta, M.A. 2008. Fuel ethanol production from pretreated agricultural residues by simultaneous saccharification and fermentation [abstract]. Society of Industrial Microbiology. p. 72.

Technical Abstract: The production of ethanol from any lignocellulosic biomass generally involves four process steps: feedstock pretreatment, enzymatic saccharification, fermentation, and ethanol recovery. Integration of these process steps is essential in order to reduce the overall production cost. Moreover, the enzymes involved in cellulose and hemicellulose hydrolysis are severely inhibited by their own products (sugars) during enzymatic saccharification. In order to relieve the product inhibition, simultaneous saccharification and fermentation (SSF) of the pretreated hydrolyzate is preferred where the fermentative microorganism can convert the sugars into ethanol as soon as they are formed. However, the optimal conditions (mainly pH and temperature) for enzymatic saccharification and fermentation are different. In addition, high initial solid content as well as high viscosity of the fermentation medium poses a serious mixing problem. Our research dealing with ethanol production by a mixed sugar utilizing recombinant ethanologenic Escherichia coli strain from dilute acid, lime, and alkaline peroxide pretreated wheat straw and rice hulls by SSF will be presented. The problems and prospects of developing an efficient SSF process for conversion of pretreated lignocellulosic feedstock to ethanol will be highlighted.