17-26: Ethanol production by liquefaction plus simultaneous saccharification and co-fermentation (L+SScF) of phosphoric-acid-pretreated Eucalyptus benthamii

Monday, April 29, 2013
Exhibit Hall
Eulogio Castro, Chemical, Environmental and Materials Engineering, University of Jaen, Jaen, Spain, Ismael U. Nieves, University of Florida, Gainesville, FL, Mike Mullinnix, University of Florida, FL, Bijay Tamang, ArborGen, Inc, FL and Lonnie O. Ingram, Microbiology & Cell Science, University of Florida, Gainesville, FL
Steam explosion pretreatment of Eucalyptus chips previously soaked in dilute phosphoric acid produced a slurry that was used for ethanol production. Following previous pretreatment results considering fermentable sugars and inhibitor generation, a Liquefaction plus Simultaneous Saccharification and co-Fermentation (L+SScF) was performed. The selected pretreated slurries were obtained using dilute phosphoric acid with the following conditions: 200 °C, 10 min retention time, and 0.5% acid soak (Condition A); and 200 ºC, 5 min retention time, 0.8% acid soak (Condition B).  The slurries were then diluted to obtain a 10% solids loading and submitted to a 6 h liquefaction step (50 °C, pH 5.0) using the commercial enzyme Cellic CTec2 from Novozyme (10% v/w of dry weight of biomass), followed by a simultaneous saccharification and co-fermentation.  After the liquefaction step, the total sugar concentration in the slurry was for 47 g/L Condition A and 51 g/L for Condition B.  The fermentation was performed by an ethanologenic Escherichia coli strain derived from the KO11 strain.  The sugars were completely consumed in 96 h with an ethanol yield as high as 0.217 and 0.243 g of ethanol per g DW of biomass for Condition A and Condition B respectively.  These results confirm the effectiveness of using phosphoric-acid-pretreated Eucalyptus for the production of ethanol via the L+SScF process.