초록
This work deals with the production of ethanol from phosphoric acid-impregnated, steam-exploded Eucalyptus benthamii. The whole conversion process, addressing pretreatment, enzymatic hydrolysis of the whole slurry, and fermentation of both C5 and C6-sugars including a presaccharification step, is covered in this study. Two separate models were developed to maximize sugar content and minimize inhibitor concentrations, resulting in xylose yields of ~50% and ~60% after pretreatment. In addition, a Liquefaction plus Simultaneous Saccharification and co-Fermentation (L+SScF) was performed to compare the fermentability of the resulting pretreated biomass. After the 6-h liquefaction step using the Cellic CTec2 enzyme from Novozyme and 10% DW pretreated biomass, the total sugar concentration in the slurry was 47g/L and 51g/L for the two conditions respectively. Enzymatic hydrolysis continued during fermentation using an ethanologenic derivative of Escherichia coli KO11. The sugars were completely consumed in 96h with product yields of 0.217 and 0.243g ethanol/g DW biomass for each condition, respectively. These yields are equivalent to 275 and 304L/tonne DW, confirming the effectiveness of the L+SScF process using phosphoric-acid-pretreated Eucalyptus.